Polycarbonate compositions and articles formed therefrom

ABSTRACT

A thermoplastic polycarbonate composition is disclosed, in various embodiments, having enhanced low-temperature ductility, UV resistance and/or fire-retardance characteristics. The composition comprises a polycarbonate, and a combination of an elastomer-modified graft copolymer and a polysiloxane-polycarbonate copolymer. The polycarbonate composition is useful for manufacture of electronic and mechanical parts, among others.

BACKGROUND

This disclosure generally relates, in various exemplary embodiments, topolycarbonate compositions and articles formed from such compositionshaving enhanced low-temperature ductility, UV resistance and/orfire-retardance characteristics, as well as uses thereof.

With their strength and clarity, polycarbonate (PC) and copolycarbonateresins offer many significant advantages and are utilized for a numberof different commercial applications. Polycarbonate materials areplaying a vital role today in applications including electronicengineering (E&E) parts, mechanical parts and so on. Unfortunately, theductility of polycarbonate resins is adversely affected with sharpnotches, high strain rate, and low temperature. To overcome thisproblem, impact modifiers such as methyl methacrylate/butadiene/styrenecopolymer (MBS), poly butylarylate (BA), and polysiloxane have beenblended with polycarbonate. For example, U.S. Patent ApplicationPublication No. 2004/0249070 to Lim et al. discloses a polycarbonatecomposition comprising a rubber modified vinyl-grafted copolymer, aphosphorous mixture of a cyclic phosphazene oligomer compound and aphosphoric acid ester as a flame retardant, and a fluorinated polyolefinresin. In the application, examples of the rubber modified vinyl-graftedcopolymer include acrylonitrile-butadiene-styrene (ABS) resin and MBSresin.

U.S. Pat. No. 6,914,090 to Seidel et al. discloses an impact-resistantand flameproofed polycarbonate molding composition suitable for makingthin-wall housing parts. The composition contains 5 percent to 20percent by weight of rubber-modified vinyl(co)polymer, 2 percent to 15percent by weight of at least one low-volatility, halogen-freeflameproofing agent, and 0.1 percent to 6 percent by weight of asilicate mineral. The rubber content of the composition is 2 percent to6 percent by weight based upon the total weight of the composition.

U.S. Pat. No. 6,063,844 to Barren et al. discloses a thermoplastic resincomposition comprising an aromatic polycarbonate resin and a rubbermodified graft copolymer. The rubber modified graft copolymer comprisesa discontinuous elastomeric phase dispersed in a continuous rigidthermoplastic phase, and at least a portion of the rigid thermoplasticphase being chemically grafted to the elastomeric phase.

U.S. Patent Application Publication No. 2003/0105226 to Cella disclosesa polysiloxane-modified polycarbonate comprising polysiloxane units andpolycarbonate units. The polysiloxane segments comprise 1 to 20polysiloxane units. Uses of other polysiloxane-modified polycarbonatesare described in U.S. Pat. No. 5,380,795 to Gosen, U.S. Pat. No.4,756,701 to Kress et al., U.S. Pat. No. 6,657,018, U.S. Pat. No.5,488,086 to Umeda et al., and EP 0 692 522B1 to Nodera, et al., forexample.

However, the introduction of rubber or polysiloxane to polycarbonatematerials has some disadvantages. For example, neither polybutylarylatenor polysiloxane has the low-temperature impact compensation capabilityfor the polycarbonate matrix. Core-shell type rubbers such as MBS, causethe polycarbonate matrix to exhibit poor thermal stability andweatherability due to the existence of unsaturated double bonds Theyalso produce poor light resistance and unsatisfactory fire-retardancecharacteristics. As such, formulations with MBS as an impact modifierare not very desirable for high temperature molding and outdoorapplications.

There accordingly remains a need in the art for polycarbonatecompositions that can readily produce an article with enhancedlow-temperature ductility, UV resistance and/or fire-retardancecharacteristics, among other properties.

SUMMARY

A polycarbonate composition is disclosed, in various embodiments, havingimproved low-temperature ductility, UV resistance, and/orfire-retardance characteristics. The composition comprises apolycarbonate, and a synergistic combination of an elastomer-modifiedgraft copolymer and a polysiloxane-polycarbonate copolymer. Thepolycarbonate composition is useful for manufacture of electronic andmechanical parts, among other applications.

A further aspect of the present disclosure provides a composition, suchas a thermoplastic composition and/or an article produced therefrom,that has improved low-temperature ductility, UV resistance, andfire-retardance characteristics. The composition comprises (i) 100 partsby weight of polycarbonate; (ii) from about 0.3 parts to about 7.0 partsby weight of an elastomer-modified graft copolymer; and (iii) from about0.3 parts to about 7.0 parts by weight of a polysiloxane-polycarbonatecopolymer.

In another aspect, the present disclosure provides an articlemanufactured from the noted thermoplastic compositions, such as a moldedor extruded electronic or a mechanical part. The article exhibitsenhanced low-temperature impact resistance, and durability (UVresistance, etc.) and/or fire retardance.

The above described characteristics and other non-limiting features areexemplified by the following detailed description.

DETAILED DESCRIPTION

Disclosed herein is a polycarbonate composition, which comprises acombination of an elastomer-modified graft copolymer and apolysiloxane-polycarbonate copolymer. The polycarbonate compositionexhibits particular desirable properties such as improvedlow-temperature ductility, UV resistance and/or fire-retardancecharacteristics, among others.

As used herein, the term “polycarbonate” refers to a polymer comprisingthe same or different carbonate units, or a copolymer that comprises thesame or different carbonate units, as well as one or more units otherthan carbonate (i.e. copolycarbonate); the term “aliphatic” refers to ahydrocarbon radical having a valence of at least one comprising a linearor branched array of carbon atoms which is not cyclic; “aromatic” refersto a radical having a valence of at least one comprising at least onearomatic group; “cycloaliphatic” refers to a radical having a valence ofat least one comprising an array of carbon atoms which is cyclic but notaromatic; “alkyl” refers to a straight or branched chain monovalenthydrocarbon radical; “alkylene” refers to a straight or branched chaindivalent hydrocarbon radical; “alkylidene” refers to a straight orbranched chain divalent hydrocarbon radical, with both valences on asingle common carbon atom; “alkenyl” refers to a straight or branchedchain monovalent hydrocarbon radical having at least two carbons joinedby a carbon-carbon double bond; “cycloalkyl” refers to a non-aromaticalicyclic monovalent hydrocarbon radical having at least three carbonatoms, with at least one degree of unsaturation; “cycloalkylene” refersto a non-aromatic alicyclic divalent hydrocarbon radical having at leastthree carbon atoms, with at least one degree of unsaturation; “aryl”refers to a monovalent aromatic benzene ring radical, or to anoptionally substituted benzene ring system radical system fused to atleast one optionally substituted benzene ring; “aromatic radical” refersto a radical having a valence of at least one comprising at least onearomatic group; examples of aromatic radicals include phenyl, pyridyl,furanyl, thienyl, naphthyl, and the like; “arylene” refers to a benzenering diradical or to a benzene ring system diradical fused to at leastone optionally substituted benzene ring; “acyl” refers to a monovalenthydrocarbon radical joined to a carbonyl carbon atom, wherein thecarbonyl carbon further connects to an adjoining group; “alkylaryl”refers to an alkyl group as defined above substituted onto an aryl asdefined above; “arylalkyl” refers to an aryl group as defined abovesubstituted onto an alkyl as defined above; “alkoxy” refers to an alkylgroup as defined above connected through an oxygen radical to anadjoining group; “aryloxy” refers to an aryl group as defined aboveconnected through an oxygen radical to an adjoining group; the modifier“about” used in connection with a quantity is inclusive of the statedvalue and has the meaning dictated by the context (e.g., includes thedegree of error associated with measurement of the particular quantity);“optional” or “optionally” means that the subsequently described eventor circumstance may or may not occur, and that the description includesinstances where the event occurs and instances where it does not; and“direct bond”, where part of a structural variable specification, refersto the direct joining of the substituents preceding and succeeding thevariable taken as a “direct bond”.

Compounds are described herein using standard nomenclature. A dash (“—”)that is not between two letters or symbols is used to indicate a pointof attachment for a substituent. For example, —CHO is attached throughthe carbon of the carbonyl (C═O) group. The singular forms “a,” “an,”and “the” include plural referents unless the context clearly dictatesotherwise. The endpoints of all ranges reciting the same characteristicor component are independently combinable and inclusive of the recitedendpoint. All references are incorporated herein by reference. The terms“first,” “second,” and the like herein do not denote any order,quantity, or importance, but rather are used to distinguish one elementfrom another.

The composition comprises effective amounts of components to produceenhanced low-temperature ductility, UV resistance and/or fire-retardancecharacteristics, among others. In one embodiment, the disclosure relatesto a polycarbonate composition comprising a polycarbonate, and asynergistic combination of an elastomer-modified graft copolymer and apolysiloxane-polycarbonate copolymer. Articles formulated from such apolycarbonate composition are also included within the scope of thepresent disclosure.

In a further embodiment, the disclosure provides a thermoplasticcomposition comprising:

-   -   (i) 100 parts by weight of polycarbonate;    -   (ii) from about 0.3 parts to about 7.0 parts by weight of an        elastomer-modified graft copolymer; and    -   (iii) from about 0.3 parts to about 7.0 parts by weight of a        polysiloxane-polycarbonate copolymer.

Although the amount of elastomer-modified graft copolymer in thisembodiment is generally from about 0.3 parts to about 7.0 parts byweight, specifically it can be from about 0.4 parts to about 5.0 partsby weight, more specifically it can be from about 0.5 parts to about 4.0parts by weight, and most specifically it can be from about 0.5 parts toabout 3.7 parts by weight.

Although the amount of polysiloxane-polycarbonate copolymer in thisembodiment is generally from about 0.3 parts to about 7.0 parts byweight, specifically it can be from about 0.4 parts to about 5.0 partsby weight, more specifically it can be from about 0.5 parts to about 4.0parts by weight, and most specifically it can be from about 0.5 parts toabout 3.7 parts by weight. Furthermore, the amount of siloxane in theentire polycarbonate composition is from about 0.06 weight percent toabout 1.4 weight percent, including from about 0.1 weight percent toabout 1 weight percent.

The elastomer-modified graft copolymers may comprise (i) an elastomeric(i.e., rubbery) polymer substrate having a Tg less than 10° C., morespecifically less than −10° C., or more specifically −40° to −85° C.,and (ii) a rigid polymeric substrate grafted to the elastomeric polymersubstrate.

The elastomer-modified graft copolymers may be prepared by firstproviding the elastomeric polymer, then polymerizing the constituentmonomer(s) of the rigid phase in the presence of the elastomer to obtainthe graft copolymer. The grafts may be attached as graft branches or asshells to an elastomer core. The shell may merely physically encapsulatethe core, or the shell may be partially or essentially completelygrafted to the core.

Suitable materials for use as the elastomer phase include, for example,conjugated diene rubbers; copolymers of a conjugated diene with lessthan 50 weight percent of a copolymerizable monomer; elastomericcopolymers of C₁₋₈ alkyl (meth)acrylate with conjugated diene; olefinrubbers such as ethylene propylene copolymers (EPR) orethylene-propylene-diene monomer rubbers (EPDM); ethylene-vinyl acetaterubbers; silicone rubbers; elastomeric C₁₋₈ alkyl(meth)acrylates;elastomeric copolymers of C₁₋₈ alkyl(meth)acrylates with butadieneand/or styrene; or combinations comprising at least one of the foregoingelastomers,

Suitable conjugated diene monomers for preparing the elastomer phase areof formula (E-1):

wherein each R₁ is independently hydrogen, C₁-C₅ alkyl, or the like.Examples of conjugated diene monomers that may be used are butadiene,isoprene, 1,3-heptadiene, methyl-1,3-pentadiene,2,3-dimethyl-1,3-butadiene, 2-ethyl-1,3-pentadiene; 1,3- and2,4-hexadienes, and the like, as well as mixtures comprising at leastone of the foregoing conjugated diene monomers. Specific conjugateddiene homopolymers include polybutadiene and polyisoprene.

Copolymers of a conjugated diene rubber may also be used, for examplethose produced by aqueous radical emulsion polymerization of aconjugated diene and one or more monomers copolymerizable therewith.Vinyl aromatic compounds may be copolymerized with the ethylenicallyunsaturated nitrile monomer to form a copolymer, wherein thevinylaromatic compounds can include monomers of formula (E-2):

wherein each R₂ is independently hydrogen, C₁-C₁₂ alkyl, C₃-C₁₂cycloalkyl, C₆-C₁₂ aryl, C₇-C₁₂ arylalkyl, C₇-C₁₂ alkylaryl, C₁-C₁₂alkoxy, C₃-C₁₂ cycloalkoxy, C₆-C₁₂ aryloxy, chloro, bromo, or hydroxy,and R₃ is hydrogen, C₁-C₅ alkyl, bromo, or chloro. Examples of suitablemonovinylaromatic monomers that may be used include styrene,3-methylstyrene, 3,5-diethylstyrene, 4-n-propylstyrene,alpha-methylstyrene, alpha-methyl vinyltoluene, alpha-chlorostyrene,alpha-bromostyrene, dichlorostyrene, dibromostyrene,tetra-chlorostyrene, and the like, and combinations comprising at leastone of the foregoing compounds. Styrene and/or alpha-methylstyrene maybe used as monomers copolymerizable with the conjugated diene monomer.

Other monomers that may be copolymerized with the conjugated diene aremonovinylic monomers such as itaconic acid, acrylamide, N-substitutedacrylamide or methacrylamide, maleic anhydride, maleimide, N-alkyl-,aryl-, or haloaryl-substituted maleimide, glycidyl(meth)acrylates, andmonomers of the generic formula (E-3):

wherein R₄ is hydrogen, C₁-C₅ alkyl, bromo, or chloro, and R₅ is C₁-C₁₂alkoxycarbonyl, C₁-C₁₂ aryloxycarbonyl, hydroxy carbonyl, or the like.Examples of monomers of formula (E-3) include, acrylic acid,methyl(meth)acrylate, ethyl(meth)acrylate, n-butyl (meth)acrylate,t-butyl(meth)acrylate, n-propyl(meth)acrylate, isopropyl(meth)acrylate,2-ethylhexyl(meth)acrylate, and the like, and combinations comprising atleast one of the foregoing monomers. Monomers such as n-butyl acrylate,ethyl acrylate, and 2-ethylhexyl acrylate are commonly used as monomerscopolymerizable with the conjugated diene monomer. Mixtures of theforegoing monovinyl monomers and monovinylaromatic monomers may also beused.

(Meth)acrylate monomers suitable for use as the elastomeric phase may becross-linked, particulate emulsion homopolymers or copolymers of C₁₋₈alkyl (meth)acrylates, in particular C₄₋₆ alkyl acrylates, for examplen-butyl acrylate, t-butyl acrylate, n-propyl acrylate, isopropylacrylate, 2-ethylhexyl acrylate, and the like, and combinationscomprising at least one of the foregoing monomers. The C₁₋₈ alkyl(meth)acrylate monomers may optionally be polymerized in admixture withup to 15 weight percent of comonomers of formulas (E-1), (E-2), or(E-3). Exemplary comonomers include but are not limited to butadiene,isoprene, styrene, methyl methacrylate, phenyl methacrylate,penethylmethacrylate, N-cyclohexylacrylamide, vinyl methyl ether, andmixtures comprising at least one of the foregoing comonomers.Optionally, up to 5 weight percent of a polyfunctional crosslinkingcomonomer may be present, for example divinylbenzene, alkylenedioldi(meth)acrylates such as glycol bisacrylate, alkylenetrioltri(meth)acrylates, polyester di(meth)acrylates, bisacrylamides,triallyl cyanurate, triallyl isocyanurate, allyl(meth)acrylate, diallylmaleate, diallyl fumarate, diallyl adipate, triallyl esters of citricacid, triallyl esters of phosphoric acid, and the like, as well ascombinations comprising at least one of the foregoing crosslinkingagents.

The elastomer phase may be polymerized by mass, emulsion, suspension,solution or combined processes such as bulk-suspension, emulsion-bulk,bulk-solution or other techniques, using continuous, semibatch, or batchprocesses. The particle size of the elastomer substrate is not critical.For example, an average particle size of 0.001 to 25 micrometers,specifically 0.01 to 15 micrometers, or even more specifically 0.1 to 8micrometers may be used for emulsion based polymerized rubber lattices.A particle size of 0.5 to 10 micrometers, specifically 0.6 to 1.5micrometers may be used for bulk polymerized rubber substrates. Particlesize may be measured by simple light transmittance methods or capillaryhydrodynamic chromatography (CHDF). The elastomer phase may be aparticulate, moderately cross-linked conjugated butadiene or C₄₋₆ alkylacrylate rubber, and preferably has a gel content greater than 70 weightpercent. Also suitable are mixtures of butadiene with styrene and/orC₄₋₆ alkyl acrylate rubbers.

The elastomeric phase may provide 5 to 95 weight percent of the totalgraft copolymer, more specifically 20 to 90 weight percent, and evenmore specifically 40 to 85 weight percent of the elastomer-modifiedgraft copolymer, the remainder being the rigid graft phase.

The rigid phase of the elastomer-modified graft copolymer may be formedby graft polymerization of a mixture comprising a (meth)acrylate monomerand optionally monovinylaromatic monomer in the presence of one or moreelastomeric polymer substrates. The above-described monovinylaromaticmonomers of formula (E-2) may be used in the rigid graft phase,including styrene, alpha-methyl styrene, halostyrenes such asdibromostyrene, vinyltoluene, vinylxylene, butylstyrene,para-hydroxystyrene, methoxystyrene, or the like, or combinationscomprising at least one of the foregoing monovinylaromatic monomers.Suitable comonomers include, for example, the above-describedmonovinylic monomers and/or monomers of the general formula (E-3). Inone embodiment, R₄ is hydrogen or C₁-C₂ alkyl, and R₅ is cyano or C₁-C₁₂alkoxycarbonyl. Specific examples of suitable comonomers for use in therigid phase include, methyl(meth)acrylate, ethyl(meth)acrylate,n-propyl(meth)acrylate, isopropyl (meth)acrylate, and the like, andcombinations comprising at least one of the foregoing comonomers.

Depending on the amount of elastomer-modified polymer present, aseparate matrix or continuous phase of ungrafted rigid polymer orcopolymer may be simultaneously obtained along with theelastomer-modified graft copolymer. Typically, such impact modifierscomprise 40 to 95 weight percent elastomer-modified graft copolymer and5 to 60 weight percent graft (co)polymer, based on the total weight ofthe impact modifier. In another embodiment, such impact modifierscomprise 50 to 85 weight percent, more specifically 75 to 85 weightpercent rubber-modified graft copolymer, together with 15 to 50 weightpercent, more specifically 15 to 25 weight percent graft (co)polymer,based on the total weight of the impact modifier.

Another specific type of elastomer-modified impact modifier comprisesstructural units derived from at least one silicone rubber monomer, abranched acrylate rubber monomer having the formulaH₂C═C(R_(d))C(O)OCH₂CH₂R_(e), wherein R_(d) is hydrogen or a C₁-C₈linear or branched alkyl group and R_(e) is a branched C₃-C₁₆ alkylgroup; a first graft link monomer; a polymerizable alkenyl-containingorganic material; and a second graft link monomer. The silicone rubbermonomer may comprise, for example, a cyclic siloxane, tetraalkoxysilane,trialkoxysilane, (acryloxy)alkoxysilane, (mercaptoalkyl)alkoxysilane,vinylalkoxysilane, or allylalkoxysilane, alone or in combination, e.g.,decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane,trimethyltriphenylcyclotrisiloxane,tetramethyltetraphenylcyclotetrasiloxane,tetramethyltetravinylcyclotetrasiloxane, octaphenylcyclotetrasiloxane,octamethylcyclotetrasiloxane and/or tetraethoxysilane.

Exemplary branched acrylate rubber monomers include iso-octyl acrylate,6-methyloctyl acrylate, 7-methyloctyl acrylate, 6-methylheptyl acrylate,and the like, alone or in combination. The polymerizable,alkenyl-containing organic material may be, for example, a monomer offormula (E-2) or (E-3), e.g., styrene, alpha-methylstyrene, or anunbranched (meth)acrylate such as methyl methacrylate, 2-ethylhexylmethacrylate, methyl acrylate, ethyl acrylate, n-propyl acrylate, or thelike, alone or in combination.

The at least one first graft link monomer may be an(acryloxy)alkoxysilane, a (mercaptoalkyl)alkoxysilane, avinylalkoxysilane, or an allylalkoxysilane, alone or in combination,e.g., (gamma-methacryloxypropyl) (dimethoxy)methylsilane and/or(3-mercaptopropyl)trimethoxysilane. The at least one second graft linkmonomer is a polyethylenically unsaturated compound having at least oneallyl group, such as allyl methacrylate, triallyl cyanurate, or triallylisocyanurate, alone or in combination.

The silicone-acrylate impact modifier compositions can be prepared byemulsion polymerization, wherein, for example at least one siliconerubber monomer is reacted with at least one first graft link monomer ata temperature from 30° C. to 110° C. to form a silicone rubber latex, inthe presence of a surfactant such as dodecylbenzenesulfonic acid.Alternatively, a cyclic siloxane such as cyclooctamethyltetrasiloxaneand tetraethoxyorthosilicate may be reacted with a first graft linkmonomer such as (gamma-methacryloxypropyl)methyldimethoxysilane, toafford silicone rubber having an average particle size from 100nanometers to 2 micrometers. At least one branched acrylate rubbermonomer is then polymerized with the silicone rubber particles,optionally in the presence of a cross linking monomer, such asallylmethacrylate and/or in the presence of a free radical generatingpolymerization catalyst such as benzoyl peroxide. This latex is thenreacted with a polymerizable alkenyl-containing organic material and asecond graft link monomer. The latex particles of the graftsilicone-acrylate rubber hybrid may be separated from the aqueous phasethrough coagulation (by treatment with a coagulant) and dried to a finepowder to produce the silicone-acrylate rubber impact modifiercomposition. This method can be generally used for producing thesilicone-acrylate impact modifier having a particle size from 100nanometers to 2 micrometers.

Processes known for the formation of the foregoing elastomer-modifiedgraft copolymers include mass, emulsion, suspension, and solutionprocesses, or combined processes such as bulk-suspension, emulsion-bulk,bulk-solution or other techniques, using continuous, semibatch, or batchprocesses.

The foregoing types of impact modifiers, including SAN copolymers, canbe prepared by an emulsion polymerization process that is free of basicmaterials such as alkali metal salts of C₆₋₃₀ fatty acids, for examplesodium stearate, lithium stearate, sodium oleate, potassium oleate, andthe like; alkali metal carbonates, amines such as dodecyl dimethylamine, dodecyl amine, and the like; and ammonium salts of amines. Suchmaterials are commonly used as surfactants in emulsion polymerization,and may catalyze transesterification and/or degradation ofpolycarbonates. Instead, ionic sulfate, sulfonate or phosphatesurfactants may be used in preparing the impact modifiers, particularlythe elastomeric substrate portion of the impact modifiers. Suitablesurfactants include, for example, C₁₋₂₂ alkyl or C₇₋₂₅ alkylarylsulfonates, C₁₋₂₂ alkyl or C₇₋₂₅ alkylaryl sulfates, C₁₋₂₂ alkyl orC₇₋₂₅ alkylaryl phosphates, substituted silicates, and mixtures thereof.A specific surfactant is a C₆₋₁₆, specifically a C₈₋₁₂ alkyl sulfonate.In the practice, any of the above-described impact modifiers may be usedproviding it is free of the alkali metal salts of fatty acids, alkalimetal carbonates and other basic materials.

In an embodiment, the elastomer-modified graft copolymer is a methylmethacrylate-butadiene-styrene (MBS) impact modifier. Other examples ofelastomer-modified graft copolymers besides MBS include but are notlimited to acrylonitrile-butadiene-styrene (ABS),acrylonitrile-styrene-butyl acrylate (ASA), methylmethacrylate-acrylonitrile-butadiene-styrene (MABS), andacrylonitrile-ethylene-propylene-diene-styrene (AES).

In an embodiment, the elastomer-modified graft copolymer comprises arubbery polymer substrate and a rigid polymer grafted to the rubberypolymer substrate. The rubbery polymer substrate comprises anelastomeric copolymer of C₁₋₈ alkyl (meth)acrylate with a conjugateddiene; and the rigid polymer comprises a polymer of monovinylaromaticmonomers. The elastomer-modified graft copolymer may also becommercially obtained. In an embodiment, a MBS copolymer may be obtainedfrom Rohm & Haas under the trade name of Paraloid EXL2691A.

The polycarbonate composition also comprises apolysiloxane-polycarbonate copolymer, also referred to as apolysiloxane-polycarbonate. The polysiloxane (also referred to herein as“polydiorganosiloxane”) blocks of the copolymer comprise repeatingsiloxane units (also referred to herein as “diorganosiloxane units”) offormula (S-1):

wherein each occurrence of R₁ is the same or different, and is a C₁₋₁₃monovalent organic radical. For example, R₁ may independently be aC₁-C₁₃ alkyl group, C₁-C₁₃ alkoxy group, C₂-C₁₃ alkenyl group, C₂-C₁₃alkenyloxy group, C₃-C₆ cycloalkyl group, C₃-C₆ cycloalkoxy group,C₆-C₁₄ aryl group, C₆-C₁₀ aryloxy group, C₇-C₁₃ arylalkyl group, C₇-C₁₃arylalkoxy group, C₇-C₁₃ alkylaryl group, or C₇-C₁₃ alkylaryloxy group.The foregoing groups may be fully or partially halogenated withfluorine, chlorine, bromine, or iodine, or a combination thereof.Combinations of the foregoing R₁ groups may be used in the samecopolymer.

The value of D in formula (S-1) may vary widely depending on the typeand relative amount of each component in the thermoplastic composition,the desired properties of the composition, and like considerations.Generally, D may have an average value of 2 to 1,000, specifically 2 to500, and more specifically 5 to 100. In one embodiment, D has an averagevalue of 10 to 75, and in still another embodiment, D has an averagevalue of 40 to 60. Where D is of a lower value, e.g., less than 40, itmay be desirable to use a relatively larger amount of thepolycarbonate-polysiloxane copolymer. Conversely, where D is of a highervalue, e.g., greater than 40, it may be necessary to use a relativelylower amount of the polycarbonate-polysiloxane copolymer.

A combination of a first and a second (or more)polysiloxane-polycarbonate copolymer may be used, wherein the averagevalue of D of the first copolymer is less than the average value of D ofthe second copolymer.

In one embodiment, the polydiorganosiloxane blocks are provided byrepeating structural units of formula (S-2):

wherein D is as defined above; each R₁ may independently be the same ordifferent, and is as defined above; and each Ar may independently be thesame or different, and is a substituted or unsubstituted C₆-C₃₀ aryleneradical, wherein the bonds are directly connected to an aromatic moiety.Suitable Ar groups in formula (S-2) may be derived from a C₆-C₃₀dihydroxyarylene compound, or any combination of two or more of thedihydroxyarylene compounds. Specific examples of suitabledihydroxyarylene compounds are 1,1-bis(4-hydroxyphenyl)methane,1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)propane,2,2-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)octane,1,1-bis(4-hydroxyphenyl)propane, 1,1-bis(4-hydroxyphenyl)n-butane,2,2-bis(4-hydroxy-1-methylphenyl)propane,1,1-bis(4-hydroxyphenyl)cyclohexane, bis(4-hydroxyphenyl sulphide), and1,1-bis(4-hydroxy-t-butylphenyl)propane. Combinations comprising atleast one of the foregoing dihydroxy compounds may also be used.

Units of formula (S-2) may be derived from the corresponding dihydroxycompound of formula (S-3):

wherein R₁, Ar, and D are as described above. Compounds of formula (S-3)may be obtained by the reaction of a dihydroxyarylene compound with, forexample, an alpha,omega-bisacetoxypolydiorangonosiloxane under phasetransfer conditions.

In another embodiment, polydiorganosiloxane blocks comprise units offormula (S-4):

wherein R₁ and D are as described above, and each occurrence of R₂ isindependently a divalent C₁-C₃₀ alkylene, and wherein the polymerizedpolysiloxane unit is the reaction residue of its corresponding dihydroxycompound. In a specific embodiment, the polydiorganosiloxane blocks areprovided by repeating structural units of formula (S-5):

wherein R₁ and D are as defined above. Each R₃ in formula (S-5) isindependently a divalent C₂-C₈ aliphatic group. Each M in formula (S-5)may be the same or different, and may be a halogen, cyano, nitro, C₁-C₈alkylthio, C₁-C₈ alkyl, C₁-C₈ alkoxy, C₂-C₈ alkenyl, C₂-C₈ alkenyloxygroup, C₃-C₈ cycloalkyl, C₃-C₈ cycloalkoxy, C₆-C₁₀ aryl, C₆-C₁₀ aryloxy,C₇-C₁₂ arylalkyl, C₇-C₁₂ arylalkoxy, C₇-C₁₂ alkylaryl, or C₇-C₁₂alkylaryloxy, wherein each n is independently 0, 1, 2, 3, or 4.

In one embodiment, M is bromo or chloro, an alkyl group such as methyl,ethyl, or propyl, an alkoxy group such as methoxy, ethoxy, or propoxy,or an aryl group such as phenyl, chlorophenyl, or tolyl; R₃ is adimethylene, trimethylene or tetramethylene group; and R₁ is a C₁₋₈alkyl, haloalkyl such as trifluoropropyl, cyanoalkyl, or aryl such asphenyl, chlorophenyl or tolyl. In another embodiment, R₁ is methyl, or amixture of methyl and trifluoropropyl, or a mixture of methyl andphenyl. In still another embodiment, M is methoxy, n is one, R₃ is adivalent C₁-C₃ aliphatic group, and R₁ is methyl.

Units of formula (S-5) may be derived from the corresponding dihydroxypolydiorganosiloxane (S-6):

wherein R, D, M, R₃, and n are as described above. Such dihydroxypolysiloxanes can be made by effecting a platinum catalyzed additionbetween a siloxane hydride of formula (S-7):

wherein R₁ and D are as previously defined, and an aliphaticallyunsaturated monohydric phenol. Suitable aliphatically unsaturatedmonohydric phenols included, for example, eugenol, 2-allylphenol,4-allyl-2-methylphenol, 4-allyl-2-phenylphenol, 4-allyl-2-bromophenol,4-allyl-2-t-butoxyphenol, 4-phenyl-2-phenylphenol,2-methyl-4-propylphenol, 2-allyl-4,6-dimethylphenol,2-allyl-4-bromo-6-methylphenol, 2-allyl-6-methoxy-4-methylphenol and2-allyl-4,6-dimethylphenol. Mixtures comprising at least one of theforegoing may also be used.

In another embodiment, the polysiloxane-polycarbonate copolymercomprises from about 50 to about 99 weight percent of carbonate unitsand from about 1 to about 50 weight percent siloxane units. Within thisrange, the polysiloxane-polycarbonate copolymer may comprise from about70 to about 98 weight percent, specifically from about 75 to about 97weight percent of carbonate units and from about 2 to about 30 weightpercent, specifically from about 3 to about 25 weight percent siloxaneunits, such as about 20 weight percent siloxane units.

In one specific embodiment, the polysiloxane-polycarbonate copolymercomprises polysiloxane units, and carbonate units derived from bisphenolA. Polysiloxane-polycarbonates may have a weight average molecularweight of 2,000 to 100,000, specifically 5,000 to 50,000 as measured bygel permeation chromatography using a crosslinked styrene-divinylbenzene column, at a sample concentration of 1 milligram per milliliter,and as calibrated with polycarbonate standards.

The polysiloxane-polycarbonate copolymer can have a melt volume flowrate, measured at 300° C./1.2 kg, of 1 to 35 cubic centimeters per 10minutes (cc/10 min), specifically 2 to 30 cc/10 min Mixtures ofpolysiloxane-polycarbonates of different flow properties may be used toachieve the overall desired flow property.

Examples of suitable polysiloxane-polycarbonate copolymers which can beutilized herein include those described in U.S. Pat. No. 6,657,018,which is fully incorporated herein by reference. Also included arepolysiloxane-polycarbonate copolymers having a larger number ofpolysiloxane units than those specifically mentioned in U.S. Pat. No.6,657,018.

In one embodiment, the composition comprises apolysiloxane-polycarbonate copolymer, such as Lexan® EXL (GeneralElectric Co.). Lexan® EXL is a polycarbonate-polysiloxane (also referredto as a polysiloxane-polycarbonate copolymer or PC-Si) copolymer with 20percent siloxane segments by weight. The resin composition comprises apolysiloxane-polycarbonate in an amount effective to maintain at leastone mechanical property of the thermoplastic composition preparedtherefrom, in the presence of further components. Compositions havingpolycarbonate-polysiloxane copolymers included have achieved greatsuccess in applications like mobile phones and automotive applications.

The polycarbonate of the disclosure can comprise repeating structuralcarbonate units of the formula (1):

in which R¹ group may be selected from any aromatic radicals, alicyclicradicals, and aliphatic radicals. In an embodiment, at least 60 percentof the R¹ groups are aromatic organic radicals.

In a further embodiment, R¹ is an aromatic organic radical, for examplea radical of the formula (2):-A¹-Y¹-A²-  (2)wherein each of A¹ and A² is a monocyclic divalent aryl radical and Y¹is a bridging radical having one or two atoms that separate A¹ from A².In an exemplary embodiment, one atom separates A¹ from A². Illustrativenon-limiting examples of radicals of this type are —O—, —S—, —S(O)—,—S(O₂)—, —C(O)—, methylene, cyclohexyl-methylene,2-[2.2.1]-bicycloheptylidene, ethylidene, isopropylidene,neopentylidene, cyclohexylidene, cyclopentadecylidene,cyclododecylidene, and adamantylidene. The bridging radical Y¹ may be ahydrocarbon group or a saturated hydrocarbon group such as methylene,cyclohexylidene, or isopropylidene.

In another embodiment, the polycarbonate can comprise repeatingstructural carbonate units of the formula (A-1):

wherein Y¹, A¹ and A² are as described above.

In yet another embodiment, polycarbonates may be produced via theinterfacial reaction of dihydroxy compounds having the formula HO—R¹—OH,which includes dihydroxy compounds of formula (3):HO-A¹-Y¹-A²-OH  (3)wherein Y¹, A¹ and A² are as described above.

In still another embodiment, polycarbonates may be produced via theinterfacial reaction of bisphenol compounds of general formula (4):

wherein R^(a) and R^(b) each represent a halogen atom or a monovalenthydrocarbon group and may be the same or different; p and q are eachindependently integers of 0 to 4; and X^(a) represents one of the groupsof formula (5):

wherein R^(c) and R^(d) each independently represent a hydrogen atom ora monovalent linear or cyclic hydrocarbon group and R^(e) is a divalenthydrocarbon group.

In yet a further embodiment, polycarbonates may be produced via theinterfacial reaction of one or more bisphenol compounds of generalformula (B-1):

wherein each G¹ is independently at each occurrence a C₆-C₂₀ aromaticradical; E is independently at each occurrence a bond, a C₃-C₂₀cycloaliphatic radical, a C₃-C₂₀ aromatic radical, a C₁-C₂₀ aliphaticradical, a sulfur-containing linkage, a selenium-containing linkage, aphosphorus-containing linkage, or an oxygen atom; “t” is a numbergreater than or equal to one; “s” is either zero or one; and “u” is awhole number including zero.

Some illustrative, non-limiting examples of suitable dihydroxy compoundsinclude the following: resorcinol; C₁₋₃ alkyl-substituted resorcinols;4-bromoresorcinol, hydroquinone, 4,4′-dihydroxybiphenyl,1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene,1,l-bis(4-hydroxyphenyl)cyclopentane;2,2-bis(3-allyl-4-hydroxyphenyl)propane;2,2-bis(2-t-butyl-4-hydroxy-5-methylphenyl)propane;2,2-bis(3-t-butyl-4-hydroxy-6-methylphenyl)propane;2,2-bis(3-t-butyl-4-hydroxy-6-methylphenyl)butane;1,3-bis[4-hydroxyphenyl-1-(1-methylethylidine)]benzene;1,4-bis[4-hydroxyphenyl-l-(1-methylethylidine)]benzene;1,3-bis[3-t-butyl-4-hydroxy-6-methylphenyl-1-(1-methylethylidine)]benzene;1,4-bis[3-t-butyl-4-hydroxy-6-methylphenyl-l-(1-methylethylidine)]benzene;4,4′-biphenol; 2,2′,6,8-tetramethyl-3,3′,5,5′-tetrabromo-4,4′-biphenol;2,2′,6,6′-tetramethyl-3,3′,5-tribromo-4,4′-biphenol;1,l-bis(4-hydroxyphenyl)-2,2,2-trichloroethane;1,1-bis(4-hydroxyphenyl)-1-cyanoethane;1,l-bis(4-hydroxyphenyl)dicyanomethane;l,l-bis(4-hydroxyphenyl)-1-cyano-1-phenylmethane;2,2-bis(3-methyl-4-hydroxyphenyl)propane;1,1-bis(4-hydroxyphenyl)norbornane; 3,3-bis(4-hydroxyphenyl)phthalide;1,2-bis(4-hydroxyphenyl)ethane; 1,3-bis(4-hydroxyphenyl)propenone;bis(4-hydroxyphenyl)sulfide; 4,4′-oxydiphenol;4,4-bis(4-hydroxyphenyl)pentanoic acid;4,4-bis(3,5-dimethyl-4-hydroxyphenyl)pentanoic acid;2,2-bis(4-hydroxyphenyl)acetic acid; 2,4′-dihydroxydiphenylmethane;2-bis(2-hydroxyphenyl)methane; bis(4-hydroxyphenyl)methane;bis(4-hydroxy-5-nitrophenyl)methane;bis(4-hydroxy-2,6-dimethyl-3-methoxyphenyl)methane;1,1-bis(4-hydroxyphenyl)ethane; 1,1-bis(4-hydroxy-2-chlorophenyl)ethane;2,2-bis(4-hydroxyphenyl)propane (bisphenol-A);1,1-bis(4-hydroxyphenyl)propane;2,2-bis(3-chloro-4-hydroxyphenyl)propane;2,2-bis(3-bromo-4-hydroxyphenyl)propane;2,2-bis(4-hydroxy-3-methylphenyl)propane;2,2-bis(4-hydroxy-3-isopropylphenyl)propane;2,2-bis(3-t-butyl-4-hydroxyphenyl)propane;2,2-bis(3-phenyl-4-hydroxyphenyl)propane;2,2-bis(3,5-dichloro-4-hydroxyphenyl)propane;2,2-bis(3,5-dibromo-4-hydroxyphenyl)propane;2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane;2,2-bis(3-chloro-4-hydroxy-5-methylphenyl)propane;2,2-bis(3-bromo-4-hydroxy-5-methylphenyl)propane;2,2-bis(3-chloro-4-hydroxy-5-isopropylphenyl)propane;2,2-bis(3-bromo-4-hydroxy-5-isopropylphenyl)propane;2,2-bis(3-t-butyl-5-chloro-4-hydroxyphenyl)propane;2,2-bis(3-bromo-5-t-butyl-4-hydroxyphenyl)propane;2,2-bis(3-chloro-5-phenyl-4-hydroxyphenyl)propane;2,2-bis(3-bromo-5-phenyl-4-hydroxyphenyl)propane;2,2-bis(3,5-disopropyl-4-hydroxyphenyl)propane;2,2-bis(3,5-di-t-butyl-4-hydroxyphenyl)propane;2,2-bis(3,5-diphenyl-4-hydroxyphenyl)propane;2,2-bis(4-hydroxy-2,3,5,6-tetrachlorophenyl)propane;2,2-bis(4-hydroxy-2,3,5,6-tetrabromophenyl)propane;2,2-bis(4-hydroxy-2,3,5,6-tetramethylphenyl)propane;2,2-bis(2,6-dichloro-3,5-dimethyl-4-hydroxyphenyl)propane;2,2-bis(2,6-dibromo-3,5-dimethyl-4-hydroxyphenyl)propane;2,2-bis(4-hydroxy-3-ethylphenyl)propane;2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane;2,2-bis(3,5,3′,5′-tetrachloro-4,4′-dihydroxyphenyl)propane;1,1-bis(4-hydroxyphenyl)cyclohexylmethane;2,2-bis(4-hydroxyphenyl)-1-phenylpropane;1,1-bis(4-hydroxyphenyl)cyclohexane;1,1-bis(3-chloro-4-hydroxyphenyl)cyclohexane;1,1-bis(3-bromo-4-hydroxyphenyl)cyclohexane;1,1-bis(4-hydroxy-3-methylphenyl)cyclohexane;1,1-bis(4-hydroxy-3-isopropylphenyl)cyclohexane;1,1-bis(3-t-butyl-4-hydroxyphenyl)cyclohexane;1,1-bis(3-phenyl-4-hydroxyphenyl)cyclohexane;1,1-bis(3,5-dichloro-4-hydroxyphenyl)cyclohexane;1,1-bis(3,5-dibromo-4-hydroxyphenyl)cyclohexane;1,1-bis(3,5-dimethyl-4-hydroxyphenyl)cyclohexane;4,4′-[1-methyl-4-(1-methyl-ethyl)-1,3-cyclohexandiyl]bisphenol (1,3BHPM);4-[1-[3-(4-hydroxyphenyl)-4-methylcyclohexyl]-1-methyl-ethyl]-phenol(2,8 BHPM); 3,8-dihydroxy-5a, 10b-diphenylcoumarano-2′,3′,2,3-coumarane(DCBP); 2-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine;1,1-bis(3-chloro-4-hydroxy-5-methylphenyl)cyclohexane;1,1-bis(3-bromo-4-hydroxy-5-methylphenyl)cyclohexane;1,1-bis(3-chloro-4-hydroxy-5-isopropylphenyl)cyclohexane;1,1-bis(3-bromo-4-hydroxy-5-isopropylphenyl)cyclohexane;1,1-bis(3-t-butyl-5-chloro-4-hydroxyphenyl)cyclohexane;1,1-bis(3-bromo-5-t-butyl-4-hydroxyphenyl)cyclohexane;1,1-bis(3-chloro-5-phenyl-4-hydroxyphenyl)cyclohexane;1,1-bis(3-bromo-5-phenyl-4-hydroxyphenyl)cyclohexane;1,1-bis(3,5-disopropyl-4-hydroxyphenyl)cyclohexane;1,1-bis(3,5-di-t-butyl-4-hydroxyphenyl)cyclohexane;1,1-bis(3,5-diphenyl-4-hydroxyphenyl)cyclohexane;1,1-bis(4-hydroxy-2,3,5,6-tetrachlorophenyl)cyclohexane;1,1-bis(4-hydroxy-2,3,5,6-tetrabromophenyl)cyclohexane;1,1-bis(4-hydroxy-2,3,5,6-tetramethylphenyl)cyclohexane;1,1-bis(2,6-dichloro-3,5-dimethyl-4-hydroxyphenyl)cyclohexane;1,1-bis(2,6-dibromo-3,5-dimethyl-4-hydroxyphenyl)cyclohexane;1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane;1,1-bis(3-chloro-4-hydroxyphenyl)-3,3,5-trimethylcyclohexane;1,1-bis(3-bromo-4-hydroxyphenyl)-3,3,5-trimethylcyclohexane;1,1-bis(4-hydroxy-3-methylphenyl)-3,3,5-trimethylcyclohexane;1,1-bis(4-hydroxy-3-isopropylphenyl)-3,3,5-trimethylcyclohexane;1,1-bis(3-t-butyl-4-hydroxyphenyl)-3,3,5-trimethylcyclohexane;1,1-bis(3-phenyl-4-hydroxyphenyl)-3,3,5-trimethylcyclohexane;1,1-bis(3,5-dichloro-4-hydroxyphenyl)-3,3,5-trimethylcyclohexane;1,1-bis(3,5-dibromo-4-hydroxyphenyl)-3,3,5-trinmethylcyclohexane;1,1-bis(3,5-dimethyl-4-hydroxyphenyl)-3,3,5-trimethylcyclohexane;1,1-bis(3-chloro-4-hydroxy-5-methylphenyl)-3,3,5-trimethylcyclohexane;1,1-bis(3-bromo-4-hydroxy-5-methylphenyl)-3,3,5-trimethylcyclohexane;1,1-bis(3-chloro-4-hydroxy-5-isopropylphenyl)-3,3,5-trimethylcyclohexane;1,1-bis(3-bromo-4-hydroxy-5-isopropylphenyl)-3,3,5-trimethylcyclohexane;1,1-bis(3-t-butyl-5-chloro-4-hydroxyphenyl)-3,3,5-trimethylcyclohexane;1,1-bis(3-bromo-5-t-butyl-4-hydroxyphenyl)-3,3,5-trimethylcyclohexane;bis(3-chloro-5-phenyl-4-hydroxyphenyl)-3,3,5-trimethylcyclohexane;1,1-bis(3-bromo-5-phenyl-4-hydroxyphenyl)-3,3,5-trimethylcyclohexane;1,1-bis(3,5-disopropyl-4-hydroxyphenyl)-3,3,5-trimethylcyclohexane;1,1-bis(3,5-di-t-butyl-4-hydroxyphenyl)-3,3,5-trimethylcyclohexane;1,1-bis(3,5-diphenyl-4-hydroxyphenyl)-3,3,5-trimethylcyclohexane;1,1-bis(4-hydroxy-2,3,5,6-tetrachlorophenyl)-3,3,5-trimethylcyclohexane;1,1-bis(4-hydroxy-2,3,5,6-tetrabromophenyl)-3,3,5-trimethylcyclohexane;1,1-bis(4-hydroxy-2,3,5,6-tetramethylphenyl)-3,3,5-trimethylcyclohexane;1,1-bis(2,6-dichloro-3,5-dimethyl-4-hydroxyphenyl)-3,3,5-trimethylcyclohexane;1,1-bis(2,6-dibromo-3,5-dimethyl-4-hydroxyphenyl)-3,3,5-trimethylcyclohexane;4,4-bis(4-hydroxyphenyl)heptane; 1,1-bis(4-hydroxyphenyl)decane;1,1-bis(4-hydroxyphenyl)cyclododecane;1,1-bis(3,5-dimethyl-4-hydroxyphenyl)cyclododecane;4,4′dihydroxy-1,1-biphenyl; 4,4′-dihydroxy-3,3′-dimethyl-1,1-biphenyl;4,4′-dihydroxy-3,3′-dioctyl-1,1-biphenyl;4,4′-(3,3,5-trimethylcyclohexylidene)diphenol;4,4′-bis(3,5-dimethyl)diphenol; 4,4′-dihydroxydiphenylether;4,4′-dihydroxydiphenylthioether;1,3-bis(2-(4-hydroxyphenyl)-2-propyl)benzene;1,3-bis(2-(4-hydroxy-3-methylphenyl)-2-propyl)benzene;1,4-bis(2-(4-hydroxyphenyl)-2-propyl)benzene;1,4-bis(2-(4-hydroxy-3-methylphenyl)-2-propyl)benzene;2,4′-dihydroxyphenyl sulfone; 4,4′-dihydroxydiphenylsulfone (BPS);bis(4-hydroxyphenyl)methane; 2,6-dihydroxy naphthalene; hydroquinone;3-(4-hydroxyphenyl)-1,1,3-trimethylindan-5-ol;1-(4-hydroxyphenyl)-1,3,3-trimethylindan-5-ol; 4,4-dihydroxydiphenylether; 4,4-dihydroxy-3,3-dichlorodiphenylether;4,4-dihydroxy-2,5-dihydroxydiphenyl ether; 4,4-thiodiphenol;2,2,2′,2′-tetrahydro-3,3,3′,3′-tetramethyl-1,1′-spirobi[1H-indene]-6,6′-diol;bis(4-hydroxyphenyl)acetonitrile; bis(4-hydroxyphenyl)sulfoxide;bis(4-hydroxyphenyl)sulfone; 9,9-bis(4-hydroxyphenyl)fluorine;2,7-dihydroxypyrene;6,6′-dihydroxy-3,3,3′,3′-tetramethylspiro(bis)indane (“spirobiindanebisphenol”); 3,3-bis(4-hydroxyphenyl)phthalide;2,6-dihydroxydibenzo-p-dioxin; 2,6-dihydroxythianthrene;2,7-dihydroxyphenoxathin; 2,7-dihydroxy-9,10-dimethylphenazine;3,6-dihydroxydibenzofuran; 3,6-dihydroxydibenzothiophene;2,7-dihydroxycarbazole, and the like, as well as combinations comprisingat least one of the foregoing dihydroxy compounds.

Specific examples of the types of bisphenol compounds represented byformula (4) include 1,1-bis(4-hydroxyphenyl)methane,1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)propane(hereinafter “bisphenol A” or “BPA”), 2,2-bis(4-hydroxyphenyl)butane,2,2-bis(4-hydroxyphenyl)octane, 1,1-bis(4-hydroxyphenyl)propane,1,1-bis(4-hydroxyphenyl)n-butane,2,2-bis(4-hydroxy-1-methylphenyl)propane,1,1-bis(4-hydroxy-t-butylphenyl)propane,3,3-bis(4-hydroxyphenyl)phthalimidine,2-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine (PPPBP),1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane (BPI), and1,1-bis(4-hydroxy-3-methylphenyl)cyclohexane (DMBPC). Combinationscomprising at least one of the foregoing dihydroxy compounds may also beused.

In one embodiment, the polycarbonate can comprise repeating structuralcarbonate units of the formula (A-2):

wherein p, q, R^(a), R^(b) and X^(a) are as described above.

In another embodiment, the polycarbonate can comprise repeatingstructural carbonate units of the formula (A-3), i.e. BPA unit:

Branched polycarbonates are also useful, as well as blends of a linearpolycarbonate and a branched polycarbonate. The branched polycarbonatesmay be prepared by adding a branching agent during polymerization. Thesebranching agents include polyfunctional organic compounds containing atleast three functional groups selected from hydroxyl, carboxyl,carboxylic anhydride, haloformyl, and mixtures of the foregoingfunctional groups. Specific examples include trimellitic acid,trimellitic anhydride, trimellitic trichloride, tris-p-hydroxy phenylethane, isatin-bis-phenol, tris-phenol TC(1,3,5-tris((p-hydroxyphenyl)isopropyl)benzene), tris-phenol PA(4(4(1,1-bis(p-hydroxyphenyl)-ethyl)alpha,alpha-dimethyl benzyl)phenol),4-chloroformyl phthalic anhydride, trimesic acid, and benzophenonetetracarboxylic acid. The branching agents may be added at a level of0.05 to 2.0 weight percent of the polycarbonate. All types ofpolycarbonate end groups are contemplated as being useful in thepolycarbonate, provided that such end groups do not significantly affectdesired properties of the polycarbonate product.

The polycarbonates may have a weight average molecular weight (Mw) offrom about 1500 to about 100,000, including from about 5000 to about50,000, and most specifically from about 10,000 to about 30,000, asmeasured by gel permeation chromatography (GPC) using a crosslinkedstyrene-divinyl benzene column, at a sample concentration of 1 milligramper milliliter, and as calibrated with polycarbonate standards.

In an embodiment, the polycarbonate has flow properties suitable for themanufacture of thin articles. Melt volume flow rate (often abbreviatedMVR) measures the rate of extrusion of a thermoplastics through anorifice at a prescribed temperature and load. Polycarbonates suitablefor the formation of thin articles may have an MVR, measured at 300°C./1.2 kg according to ASTM D1238-04, of 0.5 to 80 cubic centimeters per10 minutes (cc/10 min). In a specific embodiment, a suitablepolycarbonate composition has an MVR measured at 300° C./1.2 kgaccording to ASTM D1238-04, of 0.5 to 50 cc/10 min, and morespecifically 0.5 to 30 cc/10 min. Mixtures of polycarbonates ofdifferent flow properties may be used to achieve the overall desiredflow property.

Polycarbonates of the disclosure may include copolymers comprisingcarbonate chain units and other optional units. A specific suitablecopolymer is a polyester-polycarbonate, also known as acopolyester-polycarbonate and polyester-carbonate. Combinations ofpolycarbonates and polyester-polycarbonates may also be used. As usedherein, a “combination” is inclusive of all mixtures, blends, alloys,reaction products, and the like. In one embodiment,polyester-polycarbonates contain repeating units of formula (6):

wherein D is a divalent radical derived from a dihydroxy compound, andmay be, for example, a C₂₋₁₀ alkylene radical, a C₆₋₂₀ alicyclicradical, a C₆₋₂₀ aromatic radical or a polyoxyalkylene radical in whichthe alkylene groups contain 2 to 6 carbon atoms, specifically 2, 3, or 4carbon atoms; and T is a divalent radical derived from a dicarboxylicacid, and may be, for example, a C₂₋₁₀ alkylene radical, a C₆₋₂₀alicyclic radical, a C₆₋₂₀ alkyl aromatic radical, or a C₆₋₂₀ aromaticradical.

In one embodiment, D is a C₂₋₆ alkylene radical. In another embodiment,D is derived from an aromatic dihydroxy compound of formula (7):

wherein each R^(f) is independently a halogen atom, a C₁₋₁₀ hydrocarbongroup, or a C₁₋₁₀ halogen substituted hydrocarbon group, and n is 0 to4. The halogen is usually bromine. Examples of compounds that may berepresented by the formula (7) include resorcinol, substitutedresorcinol compounds such as 5-methyl resorcinol, 5-ethyl resorcinol,5-propyl resorcinol, 5-butyl resorcinol, 5-t-butyl resorcinol, 5-phenylresorcinol, 5-cumyl resorcinol, 2,4,5,6-tetrafluoro resorcinol,2,4,5,6-tetrabromo resorcinol, or the like; catechol; hydroquinone;substituted hydroquinones such as 2-methyl hydroquinone, 2-ethylhydroquinone, 2-propyl hydroquinone, 2-butyl hydroquinone, 2-t-butylhydroquinone, 2-phenyl hydroquinone, 2-cumyl hydroquinone,2,3,5,6-tetramethyl hydroquinone, 2,3,5,6-tetra-t-butyl hydroquinone,2,3,5,6-tetrafluoro hydroquinone, 2,3,5,6-tetrabromo hydroquinone, orthe like; or combinations comprising at least one of the foregoingcompounds.

Examples of aromatic dicarboxylic acids that may be used to prepare thepolyesters include isophthalic orterephthalic acid,1,2-di(p-carboxyphenyl)ethane, 4,4′-dicarboxydiphenyl ether,4,4′-bisbenzoic acid, and mixtures comprising at least one of theforegoing acids. Acids containing fused rings can also be present, suchas in 1,4-, 1,5-, or 2,6-naphthalenedicarboxylic acids, Specificdicarboxylic acids are terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, cyclohexane dicarboxylic acid, or mixtures thereof. Aspecific dicarboxylic acid comprises a mixture of isophthalic acid andterephthalic acid wherein the weight ratio of terephthalic acid toisophthalic acid is 91:1 to 2:98. In another specific embodiment, D is aC₂₋₆ alkylene radical and T is p-phenylene, m-phenylene, naphthalene, adivalent cycloaliphatic radical, or a mixture thereof. This class ofpolyester includes the poly(alkylene terephthalates).

In a further embodiment, carbonate units of formula (1) may also bederived from aromatic dihydroxy compounds of formula (7), whereinspecific carbonate units are resorcinol carbonate units.

Specifically, the polyester unit of a polyester-polycarbonate can bederived from the reaction of a combination of isophthalic andterephthalic diacids (or derivatives thereof) with resorcinol, bisphenolA, or a combination comprising one or more of these, wherein the molarratio of isophthalate units to terephthalate units is 91:9 to 2:98,specifically 85:15 to 3:97, more specifically 80:20 to 5:95, and stillmore specifically 70:30 to 10:90. In case the polycarbonate comprisesunits derived from resorcinol and/or bisphenol A, the molar ratio ofresorcinol carbonate units to bisphenol A carbonate units can be 0:100to 99:1, and the molar ratio of the mixed isophthalate-terephthalatepolyester units to the polycarbonate units in thepolyester-polycarbonate can be 1:99 to 99:1, specifically 5:95 to 90:10,more specifically 10:90 to 80:20. Where a blend ofpolyester-polycarbonate with polycarbonate is used, the ratio ofpolycarbonate to polyester-polycarbonate in the blend can be,respectively, 1:99 to 99:1, specifically 10:90 to 90:10

The polyester-polycarbonates may have a weight-averaged molecular weight(Mw) of 1,500 to 100,000, specifically 1,700 to 50,000, and morespecifically 2,000 to 40,000. Molecular weight determinations areperformed using gel permeation chromatography (GPC), using a crosslinkedstyrene-divinylbenzene column and calibrated to polycarbonatereferences. Samples are prepared at a concentration of about 1 mg/ml,and are eluted at a flow rate of about 1.0 ml/min.

Suitable polycarbonates can be manufactured by processes such asinterfacial polymerization and melt polymerization. Although thereaction conditions for interfacial polymerization may vary, anexemplary process generally involves dissolving or dispersing a dihydricphenol reactant in aqueous caustic soda or potash, adding the resultingmixture to a suitable water-immiscible solvent medium, and contactingthe reactants with a carbonate precursor in the presence of a suitablecatalyst such as triethylamine or a phase transfer catalyst, undercontrolled pH conditions, e.g., 8 to 11. The most commonly used waterimmiscible solvents include methylene chloride, 1,2-dichloroethane,chlorobenzene, toluene, and the like. Suitable carbonate precursorsinclude, for example, a carbonyl halide such as carbonyl bromide orcarbonyl chloride, or a haloformate such as a bishaloformates of adihydric phenol (e.g., the bischloroformates of bisphenol A,hydroquinone, or the like) or a glycol (e.g., the bishaloformate ofethylene glycol, neopentyl glycol, polyethylene glycol, or the like).Combinations comprising at least one of the foregoing types of carbonateprecursors may also be used.

A chain stopper (also referred to as a capping agent) may be includedduring polymerization. The chain-stopper limits molecular weight growthrate, and so controls molecular weight in the polycarbonate. Achain-stopper may be at least one of mono-phenolic compounds,mono-carboxylic acid chlorides, and/or mono-chloroformates.

For example, mono-phenolic compounds suitable as chain stoppers includemonocyclic phenols, such as phenol, C₁-C₂₂ alkyl-substituted phenols,p-cumyl-phenol, p-tertiary-butyl phenol, hydroxy diphenyl; monoethers ofdiphenols, such as p-methoxyphenol. Alkyl-substituted phenols includethose with branched chain alkyl substituents having 8 to 9 carbon atoms.A mono-phenolic UV absorber may be used as a capping agent. Suchcompounds include 4-substituted-2-hydroxybenzophenones and theirderivatives, aryl salicylates, monoesters of diphenols such asresorcinol monobenzoate, 2-(2-hydroxyaryl)-benzotriazoles and theirderivatives, 2-(2-hydroxyaryl)-1,3,5-triazines and their derivatives,and the like. Specifically, mono-phenolic chain-stoppers include phenol,p-cumylphenol, and/or resorcinol monobenzoate.

Mono-carboxylic acid chlorides may also be suitable as chain stoppers.These include monocyclic, mono-carboxylic acid chlorides such as benzoylchloride, C₁-C₂₂ alkyl-substituted benzoyl chloride, toluoyl chloride,halogen-substituted benzoyl chloride, bromobenzoyl chloride, cinnamoylchloride, 4-nadimidobenzoyl chloride, and mixtures thereof; polycyclic,mono-carboxylic acid chlorides such as trimellitic anhydride chloride,and naphthoyl chloride; and mixtures of monocyclic and polycyclicmono-carboxylic acid chlorides. Chlorides of aliphatic monocarboxylicacids with up to 22 carbon atoms are suitable. Functionalized chloridesof aliphatic monocarboxylic acids, such as acryloyl chloride andmethacryoyl chloride, are also suitable. Also suitable aremono-chloroformates including monocyclic, mono-chloroformates, such asphenyl chloroformate, alkyl-substituted phenyl chloroformate, p-cumylphenyl chloroformate, toluene chloroformate, and mixtures thereof.

In one embodiment, the polyester-polycarbonates may be prepared byinterfacial polymerization. Rather than utilizing a dicarboxylic acid,it is possible, and sometimes even preferred, to employ the reactivederivatives of the acid, such as the corresponding acid halides, inparticular the acid dichlorides and the acid dibromides. Thus, forexample instead of using isophthalic acid, terephthalic acid, ormixtures thereof, it is possible to employ isophthaloyl dichloride,terephthaloyl dichloride, and mixtures thereof.

Among the phase transfer catalysts that may be used are catalysts of theformula (R³)₄Q⁺X, wherein each R³ is the same or different, and is aC₁₋₁₀ alkyl group; Q is a nitrogen or phosphorus atom; and X is ahalogen atom or a C₁₋₈ alkoxy group or C₆₋₁₈ aryloxy group. Suitablephase transfer catalysts include, for example, [CH₃(CH₂)₃]₄NX,[CH₃(CH₂)₃]₄PX, [CH₃(CH₂)₅]₄NX, [CH₃(CH₂)₆]₄NX, [CH₃(CH₂)₄]₄NX,CH₃[CH₃(CH₂)₃]₃NX, and CH₃[CH₃(CH₂)₂]₃NX, wherein X is Cl⁻, Br⁻, aC₁₋₈-alkoxy group or a C₆₋₁₈ aryloxy group In one embodiment, aneffective amount of a phase transfer catalyst may be 0.1 to 10 weightpercent based on the weight of bisphenol in the phosgenation mixture. Inanother embodiment, an effective amount of phase transfer catalyst maybe 0.5 to 2 weight percent based on the weight of bisphenol in thephosgenation mixture.

Alternatively, melt processes may be used to make the polycarbonates.Generally, in the melt polymerization process, polycarbonates may beprepared by co-reacting, in a molten state, the dihydroxy reactant(s)and a diaryl carbonate ester, such as diphenyl carbonate, in thepresence of a transesterification catalyst in a Banbury® mixer, twinscrew extruder, or the like to form a uniform dispersion. Volatilemonohydric phenol is removed from the molten reactants by distillationand the polymer is isolated as a molten residue.

In an embodiment, a mixture of two or more polycarbonates may be used inthe composition, for example, a mixture of BPA-PC 22K and BPA-PC 30K.BPA-PC 22K is Bisphenol A polycarbonate resin made by an interfacialprocess with an Mw of 22,000 available from GE Plastics. BPA-PC 30K isBisphenol A polycarbonate resin made by an interfacial process with anMw of 30,000 available from GE Plastics.

In addition to the polycarbonates, polyester-polycarbonates, andcombinations of these as described above, it is also possible to usecombinations of the polycarbonates and polyester-polycarbonates withother thermoplastic polymers, for example combinations of polycarbonatesand/or polycarbonate copolymers with polyesters.

Suitable polyesters comprise repeating units of formula (6), and may be,for example, poly(alkylene dicarboxylates), liquid crystallinepolyesters, and polyester copolymers. It is also possible to use abranched polyester in which a branching agent, for example, a glycolhaving three or more hydroxyl groups or a trifunctional ormultifunctional carboxylic acid has been incorporated. Furthermore, itis sometimes desirable to have various concentrations of acid andhydroxyl end groups on the polyester, depending on the ultimate end useof the composition.

An example of a useful class of polyester is the poly(alkyleneterephthalate)s. Specific examples of poly(alkylene terephthalate)sinclude, but are not limited to, poly(ethylene terephthalate) (PET),poly(1,4-butylene terephthalate) (PBT), poly(ethylene naphthanoate)(PEN), poly(butylene naphthanoate), (PBN), (polypropylene terephthalate)(PPT), polycyclohexanedimethanol terephthalate (PCT), and combinationscomprising at least one of the foregoing polyesters. Also useful arepoly(cyclohexanedimethanol terephthalate)-co-poly(ethyleneterephthalate), abbreviated as PETG wherein the polymer comprisesgreater than or equal to 50 mole percent of poly(ethyleneterephthalate), and abbreviated as PCTG, wherein the polymer comprisesgreater than 50 mole percent of poly(cyclohexanedimethanolterephthalate). The above polyesters can include the analogous aliphaticpolyesters such as poly(alkylene cyclohexanedicarboxylate), an exampleof which ispoly(1,4-cyclohexylenedimethylene-1,4-cyclohexanedicarboxylate) (PCCD).Also contemplated are the above polyesters with a minor amount, e.g.,from 0.5 to 10 percent by weight, of units derived from an aliphaticdiacid and/or an aliphatic polyol to make copolyesters.

As described above, the disclosure provides, in one embodiment, athermoplastic composition comprising (i) 100 parts by weight ofpolycarbonate; (ii) from about 0.3 parts to about 7.0 parts by weight ofan elastomer-modified graft copolymer; and (iii) from about 0.3 parts toabout 7.0 parts by weight of a polysiloxane-polycarbonate copolymer. Itis believed that the particular proportions of the elastomer-modifiedgraft copolymer, and the polysiloxane-polycarbonate copolymer produce asynergistic effect and result in a polycarbonate product withsignificantly improved properties and characteristics.

In a further embodiment, the elastomer-modified graft copolymercomprises MBS, and the polysiloxane-polycarbonate copolymer comprises apolysiloxane-polycarbonate copolymer having about 20 percent siloxaneunits (such as Lexan® EXL). Polysiloxane-polycarbonate copolymersgenerally exhibit excellent properties such as low temperature impactresistance, good thermal and light stability, and good processingcapability. However, polysiloxane-polycarbonate copolymers are notparticularly cost-effective, and compositions comprising thepolysiloxane-polycarbonate copolymers do not provide low temperatureimpact that is as good compositions comprising MBS.

It was surprisingly found that a combination of MBS andpolysiloxane-polycarbonate copolymer results in a product with improvedproperties, such as super low temperature Notched Izod impactresistance, among others. In addition, the composition having thecombination of MBS and polysiloxane-polycarbonate copolymer has betterflame resistance and weatherability compared to compositions thatcontain MBS only. Advantageously, the compositions have a combination oflow temperature, impact resistance while having only a small amount ofrubbers, thereby overcoming the drawback associated with MBS alone, suchas poor UV resistance and poor flame retarding capability.

For example, in some embodiments, articles can be formed from thethermoplastic compositions having a Notched Izod Impact resistance at23° C. of 600 J/m or more, including from about 600 J/m to about 900 μm,such as from about 700 J/m to about 850 J/m. Additionally, the articlesexhibit a gloss retention under 1500 kj exposure of about 68 or more,including from about 60 to about 80. Moreover, the articles pass UL94 V0@ 1.6 mm.

In an embodiment, MBS and polysiloxane-polycarbonate copolymer may bepre-blended with polycarbonate, and then the mixture extruded throughtwin screws under normal polycarbonate processing conditions.

In another embodiment, the thermoplastic composition comprises (i) 100parts by weight of polycarbonate; (ii) from about 0.3 parts to about 7.0parts by weight of an elastomer-modified graft copolymer; (iii) fromabout 0.3 parts to about 7.0 parts by weight of apolysiloxane-polycarbonate copolymer; and (iv) one or more additivesselected from the group consisting of hydrolysis stabilizer,filler/reinforcing agent, visual effect enhancer, antioxidant, heatstabilizer, light stabilizer, ultraviolet light absorber, plasticizer,mold release agent, lubricant, antistatic agent, pigment, dye, flameretardant, processing aid, radiation stabilizer, and anti-drip agent.

In various embodiments, additives ordinarily incorporated in thethermoplastic compositions are selected so as not to adversely affectthe desired properties of the thermoplastic composition Mixtures ofadditives may be used. Such additives may be mixed at a suitable timeduring the mixing of the components for forming the thermoplasticcomposition.

The thermoplastic composition may comprise one or more hydrolysisstabilizers for reducing hydrolysis of ester and/or carbonate groups.Typical hydrolysis stabilizers may include carbodiimide-based additivessuch as aromatic and/or cycloaliphatic monocarbo-diimides substituted inposition 2 and 2′, such as 2,2′,6,6′-tetraisopropyldiphenylcarbodiimide.Polycarbodiimides having a molecular weight of greater than 500 gramsper mole are also suitable. Other compounds useful as hydrolysisstabilizers include an epoxy modified acrylic oligomers or polymers, andoligomers based on cycloaliphatic epoxides. Specific examples ofsuitable epoxy functionalized stabilizers include Cycloaliphatic EpoxideResin ERL-4221 supplied by Union Carbide Corporation (a subsidiary ofDow Chemical), Danbury, Conn.; and JONCRYL® ADR-4300 and JONCRYL®ADR-4368, available from Johnson Polymer Inc, Sturtevant, Wis. Whenpresent, hydrolysis stabilizers can be used in amounts of 0.05 to 1percent by weight, specifically 0.1 to 0.5 percent by weight, and morespecifically 0.12 to 0.3 percent by weight, based on the weight of thecomponent (i) polycarbonate used in the thermoplastic composition.

The thermoplastic composition may comprise a colorant such as a pigmentand/or dye additive. Suitable pigments include for example, inorganicpigments such as metal oxides and mixed metal oxides such as zinc oxide,titanium dioxides, iron oxides or the like; sulfides such as zincsulfides, or the like; aluminates; sodium sulfo-silicates, sulfates,chromates, or the like; carbon blacks; zinc ferrites; ultramarine blue;Pigment Brown 24; Pigment Red 101; Pigment Yellow 119; organic pigmentssuch as azos, di-azos, quinacridones, perylenes, naphthalenetetracarboxylic acids, flavanthrones, isoindolinones,tetrachloroisoindolinones, anthraquinones, anthanthrones, dioxazines,phthalocyanines, and azo lakes; Pigment Blue 60, Pigment Red 122,Pigment Red 149, Pigment Red 177, Pigment Red 179, Pigment Red 202,Pigment Violet 29, Pigment Blue 15, Pigment Green 7, Pigment Yellow 147and Pigment Yellow 150, or combinations comprising at least one of theforegoing pigments. When present, pigments can be used in amounts of0.01 to 10 percent by weight, based on the weight of the component (i)polycarbonate used in the thermoplastic composition.

Suitable dyes can be organic materials and include, for example,coumarin dyes such as coumarin 460 (blue), coumarin 6 (green), nile redor the like; lanthanide complexes; hydrocarbon and substitutedhydrocarbon dyes; polycyclic aromatic hydrocarbon dyes; scintillationdyes such as oxazole or oxadiazole dyes; aryl- or heteroaryl-substitutedpoly(C₂₋₈) olefin dyes; carbocyanine dyes; indanthrone dyes;phthalocyanine dyes; oxazine dyes; carbostyryl dyes;napthalenetetracarboxylic acid dyes; porphyrin dyes; bis(styryl)biphenyldyes; acridine dyes; anthraquinone dyes; cyanine dyes; methine dyes;arylmethane dyes; azo dyes; indigoid dyes, thioindigoid dyes, diazoniumdyes; nitro dyes; quinone imine dyes; aminoketone dyes; tetrazoliumdyes; thiazole dyes; perylene dyes, perinone dyes;bis-benzoxazolylthiophene (BBOT); triarylmethane dyes; xanthene dyes;thioxanthene dyes; naphthalimide dyes; lactone dyes; fluorophores suchas anti-stokes shift dyes which absorb in the near infrared wavelengthand emit in the visible wavelength, or the like; luminescent dyes suchas 7-amino-4-methylcoumarin;3-(2′-benzothiazolyl)-7-diethylaminocoumarin;2-(4-biphenylyl)-5-(4-tbutylphenyl)-1,3,4-oxadiazole;2,5-bis-(4-biphenylyl)-oxazole; 2,2′-dimethyl-p-quaterphenyl;2,2-dimethyl-p-terphenyl; 3,5,3″″,5″″-tetra-t-butyl-p-quinquephenyl;2,5-diphenylfuran; 2,5-diphenyloxazole; 4,4′-diphenylstilbene;4-dicyanomethylene-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran;1,1′-diethyl-2,2′-carbocyanine iodide;3,3′-diethyl-4,4′,5,5′-dibenzothiatricarbocyanine iodide;7-dimethylamino-1-methyl-4-methoxy-8-azaquinolone-2;7-dimethylamino-4-methylquinolone-2;2-(4-(4-dimethylaminophenyl)-1,3-butadienyl)-3-ethylbenzothiazoliumperchlorate; 3-diethylamino-7-diethyliminophenoxazonium perchlorate;2-(1-naphthyl)-5-phenyloxazole; 2,2′-p-phenylen-bis(5-phenyloxazole);rhodamine 700; rhodamine 800; pyrene; chrysene; rubrene; coronene, orthe like, or combinations comprising at least one of the foregoing dyes.When present, dyes can be used in amounts of 0.01 to 10 percent byweight, based on the total weight of the component (i) polycarbonateused in the thermoplastic composition.

The thermoplastic composition may include fillers or reinforcing agents.Where used, suitable fillers or reinforcing agents include, for example,silicates and silica powders such as aluminum silicate (mullite),synthetic calcium silicate, zirconium silicate, fused silica,crystalline silica graphite, natural silica sand, or the like; boronpowders such as boron-nitride powder, boron-silicate powders, or thelike; oxides such as TiO₂, aluminum oxide, magnesium oxide, or the like;calcium sulfate (as its anhydride, dihydrate or trihydrate); calciumcarbonates such as chalk, limestone, marble, synthetic precipitatedcalcium carbonates, or the like; talc, including fibrous, modular,needle shaped, lamellar talc, or the like; wollastonite; surface-treatedwollastonite; glass spheres such as hollow and solid glass spheres,silicate spheres, cenospheres, aluminosilicate (armospheres), or thelike; kaolin, including hard kaolin, soft kaolin, calcined kaolin,kaolin comprising various coatings known in the art to facilitatecompatibility with the polymeric matrix resin, or the like; singlecrystal fibers or “whiskers” such as silicon carbide, alumina, boroncarbide, iron, nickel, copper, or the like; fibers (including continuousand chopped fibers) such as asbestos, carbon fibers, glass fibers, suchas E, A, C, ECR, R, S, D, or NE glasses, or the like; sulfides such asmolybdenum sulfide, zinc sulfide or the like; barium compounds such asbarium titanate, barium ferrite, barium sulfate, heavy spar, or thelike; metals and metal oxides such as particulate or fibrous aluminum,bronze, zinc, copper and nickel or the like; flaked fillers such asglass flakes, flaked silicon carbide, aluminum diboride, aluminumflakes, steel flakes or the like; fibrous fillers, for example shortinorganic fibers such as those derived from blends comprising at leastone of aluminum silicates, aluminum oxides, magnesium oxides, andcalcium sulfate hemihydrate or the like; natural fillers andreinforcements, such as wood flour obtained by pulverizing wood, fibrousproducts such as cellulose, cotton, sisal, jute, starch, cork flour,lignin, ground nut shells, corn, rice grain husks or the like; organicfillers such as polytetrafluoroethylene; reinforcing organic fibrousfillers formed from organic polymers capable of forming fibers such aspoly(ether ketone), polyimide, polybenzoxazole, poly(phenylene sulfide),polyesters, polyethylene, aromatic polyamides, aromatic polyimides,polyetherimides, polytetrafluoroethylene, acrylic resins, poly(vinylalcohol) or the like; as well as additional fillers and reinforcingagents such as mica, clay, feldspar, flue dust, finite, quartz,quartzite, perlite, tripoli, diatomaceous earth, carbon black, or thelike, or combinations comprising at least one of the foregoing fillersor reinforcing agents.

The fillers and reinforcing agents may be coated with a layer ofmetallic material to facilitate conductivity, or surface treated withsilanes to improve adhesion and dispersion with the polymeric matrixresin. In addition, the reinforcing fillers may be provided in the formof monofilament or multifilament fibers and may be used either alone orin combination with other types of fiber, through, for example,co-weaving or core/sheath, side-by-side, orange-type or matrix andfibril constructions, or by other methods known to one skilled in theart of fiber manufacture. Suitable cowoven structures include, forexample, glass fiber-carbon fiber, carbon fiber-aromatic polyimide(aramid) fiber, and aromatic polyimide fiberglass fiber or the like.Fibrous fillers may be supplied in the form of, for example, rovings,woven fibrous reinforcements, such as 0-90 degree fabrics or the like;non-woven fibrous reinforcements such as continuous strand mat, choppedstrand mat, tissues papers and felts or the like; or three-dimensionalreinforcements such as braids. When present, fillers can be used inamounts of 0 to 90 percent by weight, based on the weight of thecomponent (i) polycarbonate used in the thermoplastic composition.

Visual effect enhancers, sometimes known as visual effects additives orpigments may be present in an encapsulated form, a non-encapsulatedform, or laminated to a particle comprising polymeric resin. Somenon-limiting examples of visual effects additives are aluminum, gold,silver, copper, nickel, titanium, stainless steel, nickel sulfide,cobalt sulfide, manganese sulfide, metal oxides, white mica, black mica,pearl mica, synthetic mica, mica coated with titanium dioxide,metal-coated glass flakes, and colorants, including but not limited, toPerylene Red. The visual effect additive may have a high or low aspectratio and may comprise greater than 1 facet. Dyes may be employed suchas Solvent Blue 35, Solvent Blue 36, Disperse Violet 26, Solvent Green3, Anaplast Orange LFP, Perylene Red, and Morplas Red 36. Fluorescentdyes may also be employed including, but not limited to, Permanent PinkR (Color Index Pigment Red 181, from Clariant Corporation), Hostasol Red5B (Color Index #73300, CAS # 522-75-8, from Clariant Corporation) andMacrolex Fluorescent Yellow 10GN (Color Index Solvent Yellow 160:1, fromBayer Corporation). Pigments such as titanium dioxide, zinc sulfide,carbon black, cobalt chromate, cobalt titanate, cadmium sulfides, ironoxide, sodium aluminum sulfosilicate, sodium sulfosilicate, chromeantimony titanium rutile, nickel antimony titanium rutile, and zincoxide may be employed. Visual effect additives in encapsulated formusually comprise a visual effect material such as a high aspect ratiomaterial like aluminum flakes encapsulated by a polymer. Theencapsulated visual effect additive has the shape of a bead. Whenpresent, visual effect enhancers can be used in amounts of 0.01 to 10percent by weight, based on the weight of the component (i)polycarbonate used in the thermoplastic composition.

Suitable antioxidant additives include, for example, organophosphitessuch as tris(nonyl phenyl)phosphite,tris(2,4-di-t-butylphenyl)phosphite,bis(2,4-di-t-butylphenyl)pentaerythritol diphosphite, distearylpentaerythritol diphosphite or the like; alkylated monophenols orpolyphenols; alkylated reaction products of polyphenols with dienes,such astetrakis[methylene(3,5-di-tert-butyl-4-hydroxyhydrocinnamate)]methane,or the like; butylated reaction products of para-cresol ordicyclopentadiene; alkylated hydroquinones; hydroxylated thiodiphenylethers; alkylidene-bisphenols; benzyl compounds; esters ofbeta-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionic acid with monohydricor polyhydric alcohols; esters ofbeta-(5-tert-butyl-4-hydroxy-3-methylphenyl)-propionic acid withmonohydric or polyhydric alcohols; esters of thioalkyl or thioarylcompounds such as distearylthiopropionate, dilaurylthiopropionate,ditridecylthiodipropionate,octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate,pentaerythrityl-tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionateor the like; amides ofbeta-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionic acid or the like, orcombinations comprising at least one of the foregoing antioxidants. Whenpresent, antioxidants can be used in amounts of 0.0001 to 1 percent byweight, based on the weight of the component (i) polycarbonate used inthe thermoplastic composition.

In an embodiment, octadecyl 3,5-di-tert-butyl-4-hydroxyhydrocinnamate(abbreviated as AO-1076) under the trade name of Irganox™ 1076 from CibaSpecialty Chemicals, pentaerythritol betalaurylthiopropionate withchemical abstract service number [29598-76-3] under the trade name ofSeenox™ 412S from Argus Chemical Company, andtris(2,4-di-tert-butylphenyl)phosphite (IRGAPHOS™ 168, Ciba-Geigy) wereused as the antioxidants, the amounts of which were about 0.3 percent,about 0.2 percent, and about 0.1 percent by weight respectively, basedon the weight of the component (i) polycarbonate used in thethermoplastic composition.

In another embodiment, Bis(2,4-dicumylphenyl)pentraerythritoldiphosphite under the trade name of DOVERPHOS® S9228 from Dover ChemicalCorporation was used as the antioxidant, the amount of which was about0.06 percent by weight, based on the weight of the component (i)polycarbonate used in the thermoplastic composition.

Suitable heat stabilizer additives include, for example,organophosphites such as triphenyl phosphite,tris-(2,6-dimethylphenyl)phosphite, tris-(mixed mono- anddi-nonylphenyl)phosphite or the like; phosphonates such asdimethylbenzene phosphonate or the like, phosphates such as trimethylphosphate, or the like, or combinations comprising at least one of theforegoing heat stabilizers. When present, heat stabilizers can be usedin amounts of 0.0001 to 1 percent by weight, based on the weight of thecomponent (i) polycarbonate used in the thermoplastic composition.

Light stabilizers and/or ultraviolet light (UV) absorbing additives mayalso be used. Suitable light stabilizer additives include, for example,benzotriazoles such as 2-(2-hydroxy-5-methylphenyl)benzotriazole,2-(2-hydroxy-5-tert-octyl phenyl)-benzotriazole and 2-hydroxy-4-n-octoxybenzophenone, or the like, or combinations comprising at least one ofthe foregoing light stabilizers. When present, light stabilizers can beused in amounts of 0.0001 to 1 percent by weight, based on the weight ofthe component (i) polycarbonate used in the thermoplastic composition.

Suitable UV absorbing additives include for example,hydroxybenzophenones; hydroxybenzotriazoles; hydroxybenzotriazines;cyanoacrylates; oxanilides; benzoxazinones;2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)-phenol (CYASORB™5411); 2-hydroxy-4-n-octyloxybenzophenone (CYASORB™ 531);2-[4,6-bis(2,4-dimethylphenyl)-1,3,5-triazin-2-yl]-5-(octyloxy)-phenol(CYASORB™ 1164); 2,2′-(1,4-phenylene)bis(4H-3,1-benzoxazin-4-one)(CYASORB™ UV-3638);1,3-bis[(2-cyano-3,3-diphenylacryloyl)oxy]-2,2-bis[[(2-cyano-3,3-diphenylacryloyl)oxy]methyl]propane(UVINUL™ 3030); 2,2′-(1,4-phenylene) bis(4H-3,1-benzoxazin-4-one);1,3-bis[(2-cyano-3,3-diphenylacryloyl)oxy]-2,2-bis[[(2-cyano-3,3-diphenylacryloyl)oxy]methyl]propane;nano-size inorganic materials such as titanium oxide, cerium oxide, andzinc oxide, all with particle size less than 100 nanometers; or thelike, or combinations comprising at least one of the foregoing UVabsorbers. When present, UV absorbers can be used in amounts of 0.0001to 1 percent by weight, based on the weight of the component (i)polycarbonate used in the thermoplastic composition.

Plasticizers, lubricants, and/or mold release agents additives may alsobe used. There is considerable overlap among these types of materials,which include, for example, phthalic acid esters such asdioctyl-4,5-epoxy-hexahydrophthalate;tris-(octoxycarbonylethyl)isocyanurate; tristearin; di- orpolyfunctional aromatic phosphates such as resorcinol tetraphenyldiphosphate (RDP), the bis(diphenyl)phosphate of hydroquinone and thebis(diphenyl)phosphate of bisphenol-A; poly-alpha-olefins; epoxidizedsoybean oil; silicones, including silicone oils; esters, for example,fatty acid esters such as alkyl stearyl esters, e.g., methyl stearate;stearyl stearate, pentaerythritol tetrastearate, and the like; mixturesof methyl stearate and hydrophilic and hydrophobic nonionic surfactantscomprising polyethylene glycol polymers, polypropylene glycol polymers,and copolymers thereof, e.g., methyl stearate andpolyethylene-polypropylene glycol copolymers in a suitable solvent;waxes such as beeswax, montan wax, paraffin wax or the like. Whenpresent, such materials can be used in amounts of 0.001 to 1 percent byweight, specifically 0.01 to 0.75 percent by weight, more specifically0.1 to 0.5 percent by weight, based on the weight of the component (i)polycarbonate used in the thermoplastic composition.

In an embodiment, octadecyl pentaerythritol tetrastearate (PETS), knownas Loxiol from Henkel, was used as the mold release agent/lubricant, theamount of which was about 0.28 percent by weight, based on the weight ofthe component (i) polycarbonate used in the thermoplastic composition.PETS may be injected into an extruder via nozzles.

In an embodiment, PETS was used as the mold release agent/lubricant, theamount of which was about 0.42 percent by weight, based on the weight ofthe component (i) polycarbonate used in the thermoplastic composition.

The term “antistatic agent” refers to monomeric, oligomeric, orpolymeric materials that can be processed into polymer resins and/orsprayed onto materials or articles to improve conductive properties andoverall physical performance. Examples of monomeric antistatic agentsinclude glycerol monostearate, glycerol distearate, glyceroltristearate, ethoxylated amines, primary, secondary and tertiary amines,ethoxylated alcohols, alkyl sulfates, alkylarylsulfates,alkylphosphates, alkylaminesulfates, alkyl sulfonate salts such assodium stearyl sulfonate, sodium dodecylbenzenesulfonate or the like,quaternary ammonium salts, quaternary ammonium resins, imidazolinederivatives, sorbitan esters, ethanolamides, betaines, or the like, orcombinations comprising at least one of the foregoing monomericantistatic agents.

Exemplary polymeric antistatic agents include certain polyesteramidespolyether-polyamide (polyetheramide) block copolymers,polyetheresteramide block copolymers, polyetheresters, or polyurethanes,each containing polyalkylene glycol moieties polyalkylene oxide unitssuch as polyethylene glycol, polypropylene glycol, polytetramethyleneglycol, and the like. Such polymeric antistatic agents are commerciallyavailable, for example Pelestat™ 6321 (Sanyo) or Pebax™ MH1657(Atofina), Irgastat™ P18 and P22 (Ciba-Geigy). Other polymeric materialsthat may be used as antistatic agents are inherently conducting polymerssuch as polyaniline (commercially available as PANIPOL® EB fromPanipol), polypyrrole and polythiophene (commercially available fromBayer), which retain some of their intrinsic conductivity after meltprocessing at elevated temperatures. In one embodiment, carbon fibers,carbon nanofibers, carbon nanotubes, carbon black, or any combination ofthe foregoing may be used in a polymeric resin containing chemicalantistatic agents to render the composition electrostaticallydissipative. When present, antistatic agents can be used in amounts of0.0001 to 5 percent by weight, based on the weight of the component (i)polycarbonate used in the thermoplastic composition.

Suitable flame retardants that may be added may be organic compoundsthat include phosphorus, bromine, and/or chlorine. Non-brominated andnon-chlorinated phosphorus-containing flame retardants may be preferredin certain applications for regulatory reasons, for example organicphosphates and organic compounds containing phosphorus-nitrogen bonds.

One type of exemplary organic phosphate is an aromatic phosphate of theformula (GO)₃P═O, wherein each G is independently an alkyl, cycloalkyl,aryl, alkylaryl, or arylalkyl group, provided that at least one G is anaromatic group. Two of the G groups may be joined together to provide acyclic group, for example, diphenyl pentaerythritol diphosphate. Othersuitable aromatic phosphates may be, for example, phenylbis(dodecyl)phosphate, phenyl bis(neopentyl)phosphate, phenylbis(3,5,5′-trimethylhexyl)phosphate, ethyl diphenyl phosphate,2-ethylhexyl di(p-tolyl)phosphate, bis(2-ethylhexyl)p-tolyl phosphate,tritolyl phosphate, bis(2-ethylhexyl)phenyl phosphate,tri(nonylphenyl)phosphate, bis(dodecyl)p-tolyl phosphate, dibutyl phenylphosphate, 2-chloroethyl diphenyl phosphate, p-tolylbis(2,5,5′-trimethylhexyl)phosphate, 2-ethylhexyl diphenyl phosphate, orthe like. A specific aromatic phosphate is one in which each G isaromatic, for example, triphenyl phosphate, tricresyl phosphate,isopropylated triphenyl phosphate, and the like.

Di- or polyfunctional aromatic phosphorus-containing compounds are alsouseful, for example, compounds of the formulas (18), (19), and (20)below:

wherein each G¹ is independently a hydrocarbon having 1 to 30 carbonatoms; each G² is independently a hydrocarbon or hydrocarbonoxy having 1to 30 carbon atoms; each X^(a) is independently a hydrocarbon having 1to 30 carbon atoms; each X is independently a bromine or chlorine; m is0 to 4, and n is 1 to 30. Examples of suitable di- or polyfunctionalaromatic phosphorus-containing compounds include resorcinol tetraphenyldiphosphate (RDP), the bis(diphenyl)phosphate of hydroquinone and thebis(diphenyl)phosphate of bisphenol-A, respectively, their oligomericand polymeric counterparts, and the like.

Exemplary suitable flame retardant compounds containingphosphorus-nitrogen bonds include phosphonitrilic chloride, phosphorusester amides, phosphoric acid amides, phosphonic acid amides, phosphinicacid amides, tris(aziridinyl)phosphine oxide. When present,phosphorus-containing flame retardants can be present in amounts of 0.1to 10 percent by weight, based on the weight of the component (i)polycarbonate used in the thermoplastic composition.

Halogenated materials may also be used as flame retardants, for examplehalogenated compounds and resins of formula (21):

wherein R is an alkylene, alkylidene or cycloaliphatic linkage, e.g.,methylene, ethylene, propylene, isopropylene, isopropylidene, butylene,isobutylene, amylene, cyclohexylene, cyclopentylidene, or the like; oran oxygen ether, carbonyl, amine, or a sulfur containing linkage, e.g.,sulfide, sulfoxide, sulfone, or the like. R can also consist of two ormore alkylene or alkylidene linkages connected by such groups asaromatic, amino, ether, carbonyl, sulfide, sulfoxide, sulfone, or thelike.

Ar and Ar′ in formula (21) are each independently mono- orpolycarbocyclic aromatic groups such as phenylene, biphenylene,terphenylene, naphthylene, or the like.

Y is an organic, inorganic, or organometallic radical, for example:halogen, e.g., chlorine, bromine, iodine, fluorine; ether groups of thegeneral formula OE, wherein E is a monovalent hydrocarbon radicalsimilar to X; monovalent hydrocarbon groups of the type represented byR; or other substituents, e.g., nitro, cyano, and the like, saidsubstituents being essentially inert provided that there is at least oneand preferably two halogen atoms per aryl nucleus.

When present, each X is independently a monovalent hydrocarbon group,for example an alkyl group such as methyl, ethyl, propyl, isopropyl,butyl, decyl, or the like; an aryl groups such as phenyl, naphthyl,biphenyl, xylyl, tolyl, or the like; and arylalkyl group such as benzyl,ethylphenyl, or the like; a cycloaliphatic group such as cyclopentyl,cyclohexyl, or the like. The monovalent hydrocarbon group may itselfcontain inert substituents.

Each d is independently 1 to a maximum equivalent to the number ofreplaceable hydrogens substituted on the aromatic rings comprising Ar orAr′. Each e is independently 0 to a maximum equivalent to the number ofreplaceable hydrogens on R. Each a, b, and c is independently a wholenumber, including 0. When b is not 0, neither a nor c may be 0.Otherwise either a or c, but not both, may be 0. Where b is 0, thearomatic groups are joined by a direct carbon-carbon bond.

The hydroxyl and Y substituents on the aromatic groups, Ar and Ar′, canbe varied in the ortho, meta or para positions on the aromatic rings andthe groups can be in any possible geometric relationship with respect toone another.

Included within the scope of the above formula are bisphenols of whichthe following are representative: 2,2-bis-(3,5-dichlorophenyl)-propane;bis-(2-chlorophenyl)-methane; bis(2,6-dibromophenyl)-methane;1,1-bis-(4-iodophenyl)-ethane; 1,2-bis-(2,6-dichlorophenyl)-ethane;1,1-bis-(2-chloro-4-iodophenyl)ethane;1,1-bis-(2-chloro-4-methylphenyl)-ethane;1,1-bis-(3,5-dichlorophenyl)-ethane;2,2-bis-(3-phenyl-4-bromophenyl)-ethane;2,6-bis-(4,6-dichloronaphthyl)-propane;2,2-bis-(2,6-dichlorophenyl)-pentane;2,2-bis-(3,5-dibromophenyl)-hexane; bis-(4-chlorophenyl)-phenyl-methane;bis-(3,5-dichlorophenyl)-cyclohexylmethane;bis-(3-nitro-4-bromophenyl)-methane; bis-(4-hydroxy-2,6-dichloro-3-methoxyphenyl)-methane; and2,2-bis-(3,5-dichloro-4-hydroxyphenyl)-propane 2,2bis-(3-bromo-4-hydroxyphenyl)-propane. Also included within the abovestructural formula are: 1,3-dichlorobenzene, 1,4-dibromobenzene,1,3-dichloro-4-hydroxybenzene, and biphenyls such as2,2′-dichlorobiphenyl, polybrominated 1,4-diphenoxybenzene,2,4′-dibromobiphenyl, and 2,4′-dichlorobiphenyl as well as decabromodiphenyl oxide, and the like.

Also useful are oligomeric and polymeric halogenated aromatic compounds,such as a copolycarbonate of bisphenol A and tetrabromobisphenol A and acarbonate precursor, e.g., phosgene. Metal synergists, e.g., antimonyoxide, may also be used with the flame retardant. When present, halogencontaining flame retardants can be present in amounts of 0.1 to 10percent by weight, based on the weight of the component (i)polycarbonate used in the thermoplastic composition.

Inorganic flame retardants may also be used, for example salts of C₂₋₁₆alkyl sulfonate salts such as potassium perfluorobutane sulfonate (Rimarsalt), potassium perfluoroctane sulfonate, tetraethylammoniumperfluorohexane sulfonate, and potassium diphenylsulfone sulfonate, andthe like; salts formed by reacting for example an alkali metal oralkaline earth metal (for example lithium, sodium, potassium, magnesium,calcium and barium salts) and an inorganic acid complex salt, forexample, an oxo-anion, such as alkali metal and alkaline-earth metalsalts of carbonic acid, such as Na₂CO₃, K₂CO₃, MgCO₃, CaCO₃, and BaCO₃or fluoro-anion complexes such as Li₃AlF₆, BaSiF₆, KBF₄, K₃AlF₆, KAlF₄,K₂SiF₆, and/or Na₃AlF₆ or the like. When present, inorganic flameretardant salts can be present in amounts of 0.1 to 5 percent by weight,based on the weight of the component (i) polycarbonate used in thethermoplastic composition.

In an embodiment, potassium diphenylsulfone sulfonate (KSS) from SlossCorporation was used as the inorganic flame retardant salt, the amountof which was about 3.16 percent by weight, based on the weight of thecomponent (i) polycarbonate used in the thermoplastic composition.

Radiation stabilizers may also be present, specifically gamma-radiationstabilizers. Suitable gamma-radiation stabilizers include diols, such asethylene glycol, propylene glycol, 1,3-propanediol, 1,2-butanediol,1,4-butanediol, meso-2,3-butanediol, 1,2-pentanediol, 2,3-pentanediol,1,4-pentanediol, 1,4-hexandiol, and the like; alicyclic alcohols such as1,2-cyclopentanediol, 1,2-cyclohexanediol, and the like; branchedacyclic diols such as 2,3-dimethyl-2,3-butanediol (pinacol), and thelike, and polyols, as well as alkoxy-substituted cyclic or acyclicalkanes. Alkenols, with sites of unsaturation, are also a useful classof alcohols, examples of which include 4-methyl-4-penten-2-ol,3-methyl-pentene-3-ol, 2-methyl-4-penten-2-ol, 2,4-dimethyl-4-pene-2-ol,and 9-decen-1-ol. Another class of suitable alcohols is the tertiaryalcohols, which have at least one hydroxy substituted tertiary carbon.Examples of these include 2-methyl-2,4-pentanediol (hexylene glycol),2-phenyl-2-butanol, 3-hydroxy-3-methyl-2-butanone, 2-phenyl-2-butanol,and the like, and cycloaliphatic tertiary carbons such as1-hydroxy-1-methyl-cyclohexane. Another class of suitable alcohols ishydroxymethyl aromatics, which have hydroxy substitution on a saturatedcarbon attached to an unsaturated carbon in an aromatic ring. Thehydroxy substituted saturated carbon may be a methylol group (—CH₂OH) orit may be a member of a more complex hydrocarbon group such as would bethe case with (—CR⁴HOH) or (—CR⁴ ₂OH) wherein R⁴ is a complex or asimple hydrocarbon. Specific hydroxy methyl aromatics may be benzhydrol,1,3-benzenedimethanol, benzyl alcohol, 4-benzyloxy benzyl alcohol andbenzyl benzyl alcohol. Specific alcohols are 2-methyl-2,4-pentanediol(also known as hexylene glycol), polyethylene glycol, and polypropyleneglycol. When present, radiation stabilizers are typically used inamounts of 0.001 to 1 weight percent, more specifically 0.01 to 0.5weight percent, based on the weight of the component (i) polycarbonateused in the thermoplastic composition.

Anti-drip agents may also be used, for example a fibril forming ornon-fibril forming fluoropolymer such as polytetrafluoroethylene (PTFE).The anti-drip agent may be encapsulated by a rigid copolymer asdescribed above, for example styrene-acrylonitrile copolymer (SAN). PTFEencapsulated in SAN is known as TSAN. Encapsulated fluoropolymers may bemade by polymerizing the encapsulating polymer in the presence of thefluoropolymer, for example an aqueous dispersion TSAN may providesignificant advantages over PTFE, in that TSAN may be more readilydispersed in the composition. A suitable TSAN may comprise, for example,50 weight percent PTFE and 50 weight percent SAN, based on the totalweight of the encapsulated fluoropolymer. The SAN may comprise, forexample, 75 weight percent styrene and 25 weight percent acrylonitrilebased on the total weight of the copolymer. Alternatively, thefluoropolymer may be pre-blended in some manner with a second polymer,such as for, example, an aromatic polycarbonate resin or SAN to form anagglomerated material for use as an anti-drip agent. Either method maybe used to produce an encapsulated fluoropolymer. When present, antidripagents can be used in amounts of 0.1 to 5 percent by weight, based onthe weight of the component (i) polycarbonate used in the thermoplasticcomposition.

In an embodiment, PTFE from GE plastics was used as the antidrip agent,the amount of which was about 0.48 percent by weight, based on theweight of the component (i) polycarbonate used in the thermoplasticcomposition.

Non-limiting examples of processing aids that can be used includeDoverlube® FL-599 (available from Dover Chemical Corporation),Polyoxyter® (available from Polychem Alloy Inc.), Glycolube P (availablefrom Lonza Chemical Company), pentaerythritol tetrastearate, MetablenA-3000 (available from Mitsubishi Rayon), neopentyl glycol dibenzoate,and the like. When present, processing aids can be used in amounts of0.001 to 1 percent by weight, based on the weight of the component (i)polycarbonate used in the thermoplastic composition.

The thermoplastic composition may be manufactured by methods generallyavailable in the art, for example, in one embodiment, in one manner ofproceeding, powdered polycarbonate, and any optional additive(s) arefirst blended, in a HENSCHEL-Mixer® high speed mixer. Other low shearprocesses including but not limited to hand mixing may also accomplishthis blending. The blend is then fed into the throat of an extruder viaa hopper. Alternatively, one or more of the components may beincorporated into the composition by feeding directly into the extruderat the throat and/or downstream through a sidestuffer. Additives mayalso be compounded into a masterbatch with a desired polymeric resin andfed into the extruder. The extruder is generally operated at atemperature higher than that necessary to cause the composition to flow.The extrudate is immediately quenched in a water batch and pelletized.The pellets, so prepared, when cutting the extrudate may be one-fourthinch long or less as desired. Such pellets may be used for subsequentmolding, shaping, or forming.

In a specific embodiment, a method of preparing a thermoplastic articlecomprises melt combining a polycarbonate, and any optional additive(s),to form a thermoplastic composition. The melt combining can be done byextrusion. In an embodiment, the proportions of polycarbonate, and anyoptional additive(s) are selected such that the optical properties ofthe thermoplastic composition are maximized while mechanical performanceis at a desirable level.

In a specific embodiment, the extruder is a twin-screw extruder Theextruder is typically operated at a temperature of 180 to 385° C.,specifically 200 to 330° C., more specifically 220 to 300° C., whereinthe die temperature may be different. The extruded thermoplasticcomposition is quenched in water and pelletized.

Shaped, formed, or molded articles comprising the thermoplasticcompositions are also provided. The thermoplastic compositions may bemolded into useful shaped articles by a variety of means such asinjection molding, extrusion, rotational molding, blow molding andthermoforming. In a specific embodiment, molding is done by injectionmolding. Desirably, the thermoplastic composition has excellent moldfilling capability and is useful to form articles such as, for example,optical media, including holographic storage media, thin-wall partsbottles, tubing, beakers, centrifuge tubes, pipettes, glucose meters,inhalers, syringes, dialysis fittings, sample vials, blood bags, petridishes, spatulas, connectors, trocars, stopcocks, luer locks, Y-sites,catheters, oxygenator housings, trays, dental instruments, and the like.

Unless specified differently, the flame retardancy of the compositionsdisclosed herein was determined by UL 94 Flammability Testing standardsIn this regard, there are generally two types of pre-selection testprograms conducted by Underwriters Laboratory (UL) on plastic materialsto measure flammability characteristics. The first determines thematerial's tendency either to extinguish or to spread the flame once thespecimen has been ignited. This program is described in UL 94, TheStandard for Flammability of Plastic Materials for Parts in Devices andAppliances, which is now harmonized with IEC 60707, 60695-11-10 and60695-11-20 and ISO 9772 and 9773, which is incorporated fully herein byreference.

The second test program measures the ignition resistance of the plasticto electrical ignition sources. The material's resistance to ignitionand surface tracking characteristics is described in UL 746A, which issimilar to the test procedures described in IEC 60112, 60695 and 60950.

With respect to UL 94, there are 12 flame classifications specifiedtherein that are assigned to materials based on the results ofsmall-scale flame tests. These classifications, listed below indescending order of flammability, are used to distinguish a material'sburning characteristics after test specimens have been exposed to aspecified test flame under controlled laboratory conditions.

Six of the classifications relate to materials commonly used inmanufacturing enclosures, structural parts and insulators found inconsumer electronic products (5VA, 5VB, V-0, V-1, V-2, HB).

Three of the remaining six classifications relate to low-density foammaterials commonly used in fabricating speaker grills andsound-deadening material (HF-1, HF-2, HBF).

The last three classifications are assigned to very thin films,generally not capable of supporting themselves in a horizontal position(VTM-0, VTM-1, VTM-2). These are usually assigned to substrates onflexible printed circuit boards.

During testing, specimens molded from the plastic material are orientedin either a horizontal or vertical position, depending on thespecifications of the relevant test method, and are subjected to adefined flame ignition source for a specified period of time. In sometests, the test flame is only applied once, as is the case of thehorizontal burning (HB) test, while in other tests the flame is appliedtwice or more.

A HB flame rating indicates that the material was tested in a horizontalposition and found to burn at a rate less than a specified maximum. Thethree vertical ratings, V2, V1 and V0 indicate that the material wastested in a vertical position and self-extinguished within a specifiedtime after the ignition source was removed. The vertical ratings alsoindicate whether the test specimen dripped flaming particles thatignited a cotton indicator located below the sample. UL 94 alsodescribes a method in which the test flame is applied for up to fiveapplications, in testing for a 5VA or 5VB classification. Thesesmall-scale tests measure the propensity of a material to extinguish orspread flames once it becomes ignited.

A more detailed explanation of the parameters for a UL 94 V0flammability rating utilized herein is set forth below.

The disclosure is further illustrated by the following non-limitingexamples.

EXAMPLES

In the following examples, the melt flow rate (MFR) was measured on theextruded pellets, in accordance with ASTM D1238-01. MFR is defined asthe weight of a sample that passes though an orifice with a piston whena sample of 6 to 7 grams is placed under a constant load of 1.2kilograms at 300° C. in 10 minutes, with a dwell time of 6 minutes.Results are expressed in units of grams per 10 minutes (g/10 min).

Notched Izod Impact (abbreviated as “NII”) at different temperatures wasmeasured in accordance with ASTM D256-03 using a 5 pound hammer. NII 23°C. was measured with bars aged under room temperature for 24 hours; NII0° C. was measured with bars aged under 0° C. for 24 hours; NII −10° C.was measured with bars aged under −10° C. for 24 hours; NII −20° C. wasmeasured with bars aged under −20° C. for 24 hours; and NII −30° C. wasmeasured with bars aged under −30° C. for 24 hours.

Notched Izod Impact strength (NII) and percent ductility may also bedetermined on one-eighth inch (3.2 mm) bars per ASTM D256. Izod ImpactStrength ASTM D 256 (‘NII’) may be used to compare the impactresistances of plastic materials. The results may be reported in J/m.

Gloss Retention is defined as retention of gloss of color chips after1500 kJ Xenon light exposure in accordance with ASTM G155-1, and glosswas measured according to ASTM D2457 at 60° using Garden Gloss Meter;Total FOT is defined as total flame-out-time of 5 specimens (T1 plus T2)in accordance with the UL 94 test protocol.

Flammability testing was conducted using the statistical “UL Tool” inwhich 5 bars, at the specified thickness, were burned using the UL94test protocol and the total flame-out-time was calculated. The tablebelow shows the criteria for V0, V1 and V2 under UL 94 standards.

Test type UL 94 V0 UL 94 V1 UL 94 V2 Each flame out time (t1 or t2) <=10s  <=30 s  <=30 s Total afterflame time for 5 specimen <=50 <=250 <=250(t1 + t2) Afterflame plus afterglow time for <=30 s  <=60 s  <=60 s eachspecimen (t2 + t3) Afterflame or afterglow up to the No No No holdingclamp Cotton Ignited No No Yes

The normal loading of MBS in commercialized impact modifiedpolycarbonate is generally about 4 percent. In this trial, 4 percent MBSand 4 percent polysiloxane-polycarbonate copolymer (PC-Si, labeled “EXL”in the tables) were blended into polycarbonate as control samples. Asshown in Table 1, control 1 with 4 percent polysiloxane-polycarbonatecopolymer is brittle at −30° C. Control 2 with 4 percent MBS is ductile,but compared with the same total loading of MBS/PC-Si mixtures (exp.1-exp. 4, which had 4 percent impact modifier total), the Notched IzodImpact value is lower in all temperature ranges. Surprisingly, inexperiment #5 (exp. 5), the impact modifier loading is reduced to 62percent of the original loading (with a mixture of only 1.25 percentMBS/1.25 percent polysiloxane-polycarbonate copolymer). The sample isnot only ductile, but the Notched Izod Impact is 20 percent higher thanin control 2 (which has 4 percent MBS) at −30° C. MBS/PC-Si blends havebetter gloss retention under 1500 kj UV exposure compared to sampleshaving polysiloxane-polycarbonate copolymer only or MBS only as theimpact modifier, which means the dual system gives better UV resistantcapability.

TABLE 1 MBS/PC-Si mixture in neat polycarbonate control 1 control 2 exp.1 exp. 2 exp. 3 exp. 4 exp. 5 BPA-PC 22K 57.1 57.1 57.1 57.1 57.1 57.158 BPA-PC 30K 38 38 38 38 38 38 38.6 MBS 4 0.5 2 2.75 3.5 1.25 EXL 4 3.52 1.25 0.5 1.25 PETS 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Irgaphos 168 0.1 0.10.1 0.1 0.1 0.1 0.1 Seenox 412S 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Irganox 10760.3 0.3 0.3 0.3 0.3 0.3 0.3 MFR g/10 min 15 15.6 14.4 15 15.2 15.7 14.7NII 23° C. J/m 860 731 844 752 757 723 796 NII 0° C. J/m 832 682 790 722720 697 786 NII −10° C. J/m 778 685 786 744 733 692 750 NII −20° C. J/m688 643 711 662 838 628 718 NII −30° C. J/m 255 602 741 678 664 621 723Gloss retention % 66.4 57.1 74.9 68.3 68.7 74 77.1

The flame retardant capability of this MBS/PC-Si mixture was alsoevaluated. From Table 2, it is clear that the formulation with thepolysiloxane-polycarbonate only (Exp. 6) exhibits good flame retardantperformance with total FOT 22.7 of seconds and passes UL 94 V0 @ 1.6 mm,but the sample is brittle at −20° C. Formulations with MBS only (Exp.8-Exp. 10) show good low temperature impact ductility, but the total FOT(flame out time) is much longer than in samples with PC-Si only.Additionally, these formulations do not pass the UL 94 V0 @ 1.6 mm test.It is very clear that higher loading of MBS results in worse FRperformance. The combination of MBS/PC-Si (Exp. 7) gives an excellentbalance of low temperature impact and FR capability. With the sameloading of impact modifier, the composition can pass UL 94 V0 @ 1.6 mmand maintain ductility at −20° C.

TABLE 2 MBS/EXL mixture with FR package. Exp. 6 Exp. 7 Exp. 8 Exp. 9 Exp10 BPA-PC 22K 33.4 33.4 33.4 33.4 33.4 BPA-PC 30K 62 62 62 62 62 MBS 1.51.5 3 4 EXL 3 1.5 KSS 0.3 0.3 0.3 0.3 0.3 PTFE 0.46 0.46 0.46 0.46 0.46PETS 0.4 0.4 0.4 0.4 0.4 Doverphos S9228 0.06 0.06 0.06 0.06 0.06 MFRg/10 min 6.46 6.46 6.74 6.23 5.89 NII 23° C. J/m 917 883 882 847 824 NII−10° C. J/m 821 825 831 823 760 NII −20° C. J/m 389 748 777 747 741 UL94 rating @ 1.6 mm V0 V0 V2 V2 V2 Total FOT of 5 bars 22.7 17.8 35.848.2 154

Accordingly, the use of dual impact modifiers (MBS and PC-Si) inpolycarbonate provides excellent low temperature ductility concurrentlywith improved UV resistance and FR performance.

The exemplary embodiment has been described with reference to thepreferred embodiments. Obviously, modifications and alterations willoccur to others upon reading and understanding the preceding detaileddescription. It is intended that the exemplary embodiment be construedas including all such modifications and alterations insofar as they comewithin the scope of the appended claims or the equivalents thereof.

1. A thermoplastic composition comprising (i) 100 parts by weight ofpolycarbonate; (ii) an elastomer-modified graft copolymer; and (iii) apolysiloxane-polycarbonate copolymer, wherein the elastomer-modifiedgraft copolymer and the polysiloxane-polycarbonate copolymer togetherequal 4 weight percent or less, and the composition has a Notched IzodImpact strength at −30° C. of about 720 J/m or greater when measuredaccording to ASTM D256.
 2. The thermoplastic composition according toclaim 1, wherein the elastomer-modified graft copolymer comprises methylmethacrylate-butadiene-styrene copolymer (MBS).
 3. The thermoplasticcomposition according to claim 1, wherein the polysiloxane-polycarbonatecopolymer comprises repeating siloxane units of formula (S-1):

wherein each occurrence of R₁ is same or different, and is a C₁₋₁₃monovalent organic radical; and D may have an average value of 2 to1,000.
 4. The thermoplastic composition according to claim 1, whereinthe polyslioxane-polycarbonate copolymer comprises from about 50 toabout 99 weight percent of carbonate units and from about 1 to about 50weight percent siloxane units.
 5. The thermoplastic compositionaccording to claim 1, wherein the polysiloxane-polycarbonate copolymercomprises from about 2 weight percent to about 30 weight percentsiloxane units.
 6. The thermoplastic composition according to claim 1,wherein the polysiloxane-polycarbonate copolymer comprises about 20percent siloxane segments by weight.
 7. The thermoplastic compositionaccording to claim 1, wherein the amount of siloxane present in thecomposition is from about 0.06 weight percent to about 1.4 weightpercent
 8. The thermoplastic composition according to claim 1, whereinthe polycarbonate comprises repeating structural carbonate units of theformula (A-1):

wherein each of A¹ and A² is a monocyclic divalent aryl radical and Y¹is a bridging radical having one or two atoms that separate A¹ from A².9. The thermoplastic composition according to claim 1, wherein thepolycarbonate comprises repeating structural carbonate units of theformula (A-2):

wherein R^(a) and R^(b) each represent a halogen atom or a monovalenthydrocarbon group and may be the same or different; p and q are eachindependently integers of 0 to 4; and X^(a) represents one of the groupsof formula (5):

wherein R^(c) and R^(d) each independently represent a hydrogen atom ora monovalent linear or cyclic hydrocarbon group and R^(e) is a divalenthydrocarbon group.
 10. The thermoplastic composition according to claim1, wherein the polycarbonate comprises repeating structural carbonateunits of the formula (A-3):


11. The thermoplastic composition according to claim 1, wherein thepolycarbonate comprises a mixture of bisphenol A polycarbonates(BPA-PCs) with molecular weight of about 22,000 and 30,000 respectively12. The thermoplastic composition according to claim 1, furthercomprising one or more optional additives selected from the groupconsisting of hydrolysis stabilizer, filler/reinforcing agent, visualeffect enhancer, antioxidant, heat stabilizer, light stabilizer,ultraviolet light absorber, plasticizer, mold release agent, lubricant,antistatic agent, pigment, dye, flame retardant, processing aid,radiation stabilizer, anti-drip agent, and combinations thereof.
 13. Thethermoplastic composition according to claim 12, wherein the flameretardant agent comprises potassium diphenylsulfone sulfonate (KSS). 14.The thermoplastic composition according to claim 1, further comprisingpolytetrafluoroethylene (PTFE).
 15. An article made from the compositionaccording to claim 1,
 16. The article according to claim 15, wherein thearticle is capable of achieving a UL 94 V0 rating at 1.6 mm.
 17. Athermoplastic composition comprising (i) 100 parts by weight ofpolycarbonate; (ii) an elastomer-modified graft copolymer; (iii) apolysiloxane-polycarbonate copolymer; and (iv) from about 0.1 parts toabout 10.0 parts by weight of a flame retardant agent, wherein theelastomer-modified graft copolymer and the polysiloxane-polycarbonatecopolymer together equal 4 weight percent or less; the weight ratio ofthe elastomer-modified graft copolymer to the polysiloxane-polycarbonatecopolymer is about 1:1; and the composition has a Notched Izod Impactstrength at −30° C. of from about 720 J/m to about 740 J/m when measuredaccording to ASTM D256.
 18. A thermoplastic composition comprising apolycarbonate, an elastomer-modified graft copolymer, and apolysiloxane-polycarbonate copolymer, wherein the elastomer-modifiedgraft copolymer and the polysiloxane-polycarbonate copolymer togetherequal about 2.5 weight percent or less, and wherein an article made fromthe composition can achieve a UL 94 V0 rating at 1.6 mm whilemaintaining a Notched Izod Impact strength according to ASTM D256 at−30° C. of about 720 J/m.
 19. An article formed from a compositioncomprising (i) 100 parts by weight of a polycarbonate; (ii) anelastomer-modified graft copolymer; and (iii) apolysiloxane-polycarbonate copolymer, wherein the elastomer-modifiedgraft copolymer and the polysiloxane-polycarbonate copolymer togetherequal about 2.5 weight percent; and wherein the article exhibits aNotched Izod Impact according to ASTM D256 at −30° C. of about 720 J/mand gloss retention under 1500 kJ UV exposure of 77 or more.
 20. Anarticle formed from a thermoplastic composition comprising (i) 100 partsby weight of a bisphenol-A polycarbonate; (ii) a(meth)acrylate-butadiene-styrene copolymer; and (iii) apolysiloxane-polycarbonate copolymer; wherein the(meth)acrylate-butadiene-styrene copolymer and thepolysiloxane-polycarbonate copolymer together equal about 2.5 weightpercent or less; and wherein the molded article exhibits a Notched IzodImpact according to ASTM D256 at −30° C. of about 720 J/m and achieves aUL94 V0 rating at 1.6 mm.